Module 5 Flashcards
1
Q
Name an enzyme added to nectar by a honey bee.
A
…Invertase/Sucrase…
2
Q
Name the tough wall surrounding the egg.
A
…Chorion……………
3
Q
Name the protein found in fat cells of adult workers in winter.
A
……vitellogenin
4
Q
Name the hooks on the rear wings of the honey bee.
A
hamuli
5
Q
Where is the antenna cleaner found?
A
…Front leg between the tibia and basitarsus
6
Q
What is the name given to segment A1 of the honey bee?
A
…Propodeum
7
Q
How many ostia does a bee have?
A
5 pairs
8
Q
Name the alarm pheromone not produced in the sting.
A
2 heptanone
9
Q
Name one constituent of Nasonov pheromone.
A
…geraniol. also citral, nerolic acid
10
Q
Juvenile hormone is secreted by which organ?
A
Corpra allata
11
Q
compare reproductive organs in newly hatched drone to older drone
A
In the newly emerged drone the testes are bigger but are shrinking as the sperm
leave the testes.
12
Q
Describe how sperms are formed from germinal cells.
A
The testes of the drone are made of approx. 150 tubules each with the
germanium at the anterior end.
-The germanium bud of cells i.e. divide by mitosis forming spermatogonia.
-The spermatogonia move down the tubules and form into groups encased in a membrane and are then called spermatocytes.
-The spermatocytes grow and divide again by mitosis and separate become distinct
cells encased in the membrane.
-To this point they retain the appearance of a normal cell.
-They then undergo the abortive meiotic division and become spermatids.
-They then finally change their shape becoming long thin cells with tails and are
called spermatozoa.
-Much of this development starts in the larval stage and all is completed in the
pupae.
-Once the imago emerges the spermatozoa has already started to leave the testes
for the seminal vesicles via the vas deferens.
13
Q
How does the larva change in the first 24 hours after its cell is sealed?
A
the larvae finishes eating, then moves around, then empties the waste from
the digestive and Malpighian tubules, then spins a cocoon.
14
Q
What is a prepupa?
A
A prepupa is a developmental stage in the life cycle of a bee that occurs before the
pupal stage
15
Q
List 7 changes that take place during prepupal development.
A
- The mouth parts elongate gradually
- The antennae appear
- The compound eyes will become pronounced
- Sting begins to develop
- Small legs appear with their joints in place and start to grow
- The wings appear with small pads on the sides of the thorax
Segments A8,A9 and A10 are telescoped into A7
16
Q
Outline how the reproductive system of the drone changes after emergence.
A
1.The Testes gradually shrink to become small triangular-shaped structures found
towards the front (anterior) of the abdomen as sperm fill the seminal vesicles.
As the seminal vesicles fill they become larger.
No further spermatozoa are formed.
The mucous glands enlarge as the drone reaches maturity.
17
Q
Name the valves at either end of the ventriculus.
A
Proventriculus and the pyloric valve
18
Q
Describe the structure and function of the valve at the anterior end of the ventriculus.
A
The proventriculus is basically a one way valve that prevents anything that goes through
it into the ventriculus to not be able to return through it. 1
The valve has 4 flaps that are covered in bristles 1 and 4 pouches lead off of the flaps1
that move in a gulping action and collect the solid parts including pollen 1
pollen is formed into a bolus and passed down into the ventriculus
Any liquid food that interacts with the proventriculus can be pushed back into the crop ie nectar
19
Q
Give the functions of the ventriculus.
A
- Digestion: Produces enzymes that break down food, pollen being the main source
of protein is broken down by proteases and lipids by lipases and nectar for
carbohydrate such as sucrose by sucrase. - Produces mucous which forms the periotropic membrane which protects the wall of the ventriculus from damage from the pollen and lots of pathogens such as EFB.
3 Absorbtion of the simple product of digestion across the wall of the ventriculus as amino acids(proteins), fatty acids and glycerol(lipids) and glucose and
fructose(carbohydrates).
4 Peristaltic actions act on the walls of the ventriculus help mix food and enzymes and once digestion and absorbtion are completed, the pyloric valve at the distal end opens and the waste material is passed into the small intestine.
20
Q
A
21
Q
How is the drone adapted to ensure successful mating?
A
The antenna are larger with an extra annuli on the flagellum i.e. the
drone has 11. Therefore more room for extra sensilla.
2. The drone has significantly more sensilla placode the odour sense
organ which are specialized to pick up queen pheromone to a level
of a single molecule.
3. The drone has much bigger eyes with 10,000 ommatidia per eye to
use to catch sight of the queen these push the ocelli to the front of
the head they are so large.
4. The thorax is bigger and filled with large flight muscles allowing the
drone to fly faster and for longer.
5. The drones thorax is hairier believed to keep the thorax warmer
ready for flight.
6. The abdominal musculature is well developed which is important to
push out the endophallus.
7. The drone’s pheromones allow him to be accepted in all colonies
time or year and provisions permitting so he can be fed if required to
return to a drone congregation area.
22
Q
List 4 functions of the cuticle of an adult honey bee.
A
It provides a waterproof layer and reduces fluid loss.
2. It acts as an exoskeleton and protects internal organs
3. It provides a structure onto which muscles can attach to allow movement.
4. It sclerotised parts form sturctures such as the mandible used for feeding
and defence and comb building and the sting involved in defence.
5. It is the first line of defence again invasion of pathogens.
23
Q
Distinguish between endocuticle and exocuticle.
A
-Both are part of the cuticle, the endocuticle retains flexibility and is derivedmainly from chitin.
-The exocuticle is present outside the endocuticle but firmy attached to it. It is
sclerotised and is much harder and more regid. It contains the protein sclerotin.
24
Q
Describe how a new exocuticle develops during a larval moult.
A
-The cells of the epidermis become active and divide
-The cuticle separates from the epidermis.
-moulting fluid exudes from the epithelial cells into the space.
-A new epicuticle is formed by the epidermis
-enzymes in the moulting fluid are activated and dissolve the old endocuticle.
This is absorbed.
-the larvae swallows air causing an increase in pressure and ruptures the old
exocuticle.
25
Where and why is the endocuticle retained in some areas of the exoskeleton?
Trachea, bursa copulatrix, oesophagus and small intestine and rectum. It is
retained as these structures are ectodermal in origin.
26
What is an apodeme?
An internal ridge or thickening in a sclerites where the
muscles attach.
27
Define complete metamorphosis.
The development of an insect through four separate and very distinct stages- egg, larva,pupa and adult.
28
List the stages of metamorphosis in the honey bee.
Egg
(d) larva
(e) pupa
adult
29
digestive;develops to maturity:
larval stage- ventriculus is the largest structure, it is not connected to the hind
gut until later stages so the larvae cannot pass waste. As there are no
working mouthparts it can only suck in semi liquid food. The ventriculus is
derived from the endoderm and even in the larval stages produces enzymes
to break down pollen and carbohydrates fed. The stomadeum and
proctodeum are derived from ectoderm and retain a cuticular lining and are
not therefore invoved in digestion or assimulation.
Aprox 24hs post capping, feeding stops, the connection between the
ventriculus and the proctodeum breaks down, the larvae empties itself into its
cell, some of the waste is caught up with the silk formed from the spinnerets
and the larvae builds a cocoon.
Pre-pupal: there is the early development of mouth parts this continues in the
pupal stage. The petiole also appears at this stage.
(i) Pupal form- The digestive system breaks down completely and rebuilds in
final form. Consisting of cibarium, pharynx,(Head) oesophagus (thorax)honey
crop. Ventriculus, small intestine, rectum and anus all found in the abdomen.
All apart from the ventriculus are lined with cuticle. The crop, oesophagus,
ventriculus, small intestine and rectum. The muscles required for peristalsis
are also developed again during this stage. .
30
excretory; system development
The larva has four malphigian tubules, these will also store nitrogenous
waste. The connection to the intestine is closed at this stage. They fill and get
bigger as the larvae grow from L1-L5.
Once the cell is capped, the malphigian tubules connect to the gut, the gut is
fully connected and waste passes through it into the cocoon.
Pupal stage- 4 Malphigian tubules break down, and approx 100 are built.
The respiratory system is a tracheal system and develops from the ectoderm
in the egg and in the larvae has 10 pairs of open spiracles one pair in each
segment T2-A8.In the larvae fluid is found in the trachea There are no air
sacs in the larval stage. It is believed that much diffusion can occur through
the larval skin also. As the larvae grows further development occurs and
tracheoles are found close to all tissues. The main trachea unite down each
side of the body.
The pupal stage- much of the structure is retained the main tracheal branes
develop into air sacs, further branching of the trachea and tracheoles are
required as the insect enlarges. The spiracles develop muscles required to
control their apertures required for efficient ventilation and reduction of fluid
loses.
The tracheal and tracheoles are lined with cuticle which is shed with each
moult.
31
nervous system development
Larval stage- Develops from the ectoderm, the spinal cord is visable as two
ridges in the day 2 egg.
11 thickenings in the ridges form and unite to form ganglia. Nerve fibers are
developed and connect to all areas of the body.
The brain and sub-oesophageal ganglion are formed separately from the
ectoderm of the head. Each of the 3 thoracic segments have their own
ganaglia as has the first 6 abdominal segments, abdominal segments 7-10
are supplied by a fused ganglion.
Pupal Stage- brain enlarges in conjunction with eye and antennae
development. Sensilla develop. A number of the ganglia fuse together to
leave 7 in the pupae and imago. Nerves which served pupal structures which
no longer exist are reabsorbed while new nerve are developed to supply
developing structures such as muscles.
32
reproductive system development
larval stage- the ovaries begin to develop for workers and queens, they are
very small in workers, but in queens can be 2mm long. Drone develop testes
in the same area, between A4 and A6.It is believed that they are derived from
cleavage cells. The internal tubular structure is well developed in the larvae.
These are not broken down but continue to grow, both male and female.
Testes reach full development in pupa, then shrink in size.
Other parts of the reproductive system develop in the pupae as the segments
A8,9 and 10 are telescoped into A7, most of the remaining reproductive
system is derived from ectoderm.
The development of these structures in the female is controlled by gene
regulation which is influenced by diet and hormone levels such as juvenile
Hormone.
33
silk glands development
Larval stage-2 silk glands are present and open to the outside via the
spinneret on the head below the larval mouth. These are long glandular
structures that lie below the midgut. After capping, these produce silk that the
larvae spins into a cocoon.
Pupal Stage- the silk glands are reabsorbed and their remmnants develop into thoracic salivary glands.
34
How does the sting work?
(b) Describe how muscles enable this structure to operate. Two muscles
only are responsible for the functioning of the sting apparatus; the protractor
muscle (depicted as the muscular body immediately beneath (J) above), and the
retractor muscle (shown beneath (E) above).
There are no other muscles used in the mechanism.
These muscles are responsible for the articulation of the quadrate plates, which
are moving plates, located (as are the two other types of plate - the semi-moveable
(‘rocking’) triangular plates and the fixed oblong plates) on each side of the sting.
Each quadrate plate articulates with the top of its triangular plate. When the
quadrate plates are pulled backwards (by the retractor muscle), the triangular plate
rocks on the oblong plate, and the movement is transferred to the arching ramii
causing retraction of the lancets. Equally when the quadrate plate is pulled
forwards by the protractor muscles the triangular plate rocks forwards and the
lancet is protracted.
These arching ramii which are thus moved back and forth are actually flexible
extensions of the lancets, and the action of the protractor and retractor muscles
thus causes the lancets to move up and down on ‘rails’ attached to the stylet.
The lancets thus move up and down in opposing/reciprocating fashion (like hedge-
trimmer blades).
When they do so, the attached umbrella valves (which ‘inflate’ on a downward
stroke and collapse on an upward stroke) ‘scoop’ venom, which is forced through
this one-way valve into the venom canal, which is the central chamber of the
structure comprising the stylet and the lancet, and down which the venom then
flows, and is delivered to its target, as described in c) below.
35
how is the venom delivered to the victim?
To deliver its sting, the bee bends its abdomen downwards (into an almost vertical
position) due to the actions of the muscles that connect the abdominal plates. The
shaft which normally encloses the sting mechanism is swung upwards - and the
weapon is thereby effectively ‘unsheathed’.
This posture ensures that the sting shaft enters roughly perpendicularly into the
skin of the victim - which is the most efficient, since venom is delivered more
deeply and the route through the skin is shortest. The force from the bee's legs, the
muscles of the abdomen and the effect of the backward raked barbs, as the
lancets reciprocate alternately, all combine to produce a thrust that drives the
penetration of the sting.
Internal mechanism:
Venom is produced by two venom (/acid) glands ‘upstream’ of venom sac. The
acid glands are long slender tubules, with secretory cells along their length.
These open into the anterior end of the venom sac, which acts as a reservoir for
the poison. This in turn opens into the cavity of the venom bulb at the base of the
sting. The posterior end of the venom bulb transitions into the stylet (which is
attached by ‘rails’ to the two lancets).The poison sac walls have no muscles, and the venom therefore is not expelled by
any related contraction; ultimately it is driven through the canal of the sting by the
action of the sting lancets and their valves, as described in b) above.
36
venom and the sting
Venom is produced in the venom glands which are tubular gland without any musculature. Venom
flows out into the venom sac. Worker honey bees produce venom from day 18 while queens have
venom on emerging.
2. The venom sac acts as a reservoir for venom.
3. A wide duct leaves the venom sac and enter the bulbs close to where the first ramus meet. The duct
is always held open by ridged rings of tissue
4. The bulb of the venom canal is a widening of the (mainly) stylet dorsally and two lancets ventrally and
it is where the 2 umbrella valves reside.
5. The umbrella valves are soft tissue structures attached and move with the lancets.
5. They are downward pointing cone shape and expand as the lancet is driven down into the victim.
6. This forces venom into the venom canal made by the two lancets and the shorter stylet and out
between the ends of the moving lancets.
7. The lancets move over the stylet similar to a monorail ensuring that the venom does leak out until it
reaches the point where the stylet stops. The sawing action means the venom makes maximum contact
with the tissues of the victim.
8.The action of the abdominal musculature, legs and muscles of the sting apparatus on the plates
deliver the venom to the victim.
37
the sting mechanism
1. 1.The abdominal muscles move the abdomen perpendicular to the bee long axis. The muscles
between the ventral aspects of the sternites contract causing them to pull together and shortening the
section while dorsal musculature between the sclerites relax slightly while the muscles
2. The sting is moved from its normal resting place at the roof of the abdomen to the stinging position by
a separate group of muscles
3. The protractor muscles on one side of the sting apparatus contract (front of the oblong plate to the
rear of the quadrate plate)
4. this causes the (mobile)quadrate plate to move outwards and forwards relative to the oblong
plate(fixed).
5. This in turn causes the triangular plate to pivot as it is fixed to the oblong plate and move the first
ramus with which it is continuous.
6. The first ramus slides along the fixed second ramus and becomes a lancet.
7. The second ramus becomes the bulb and the stylet of the sting
8. The first ramus in turn continues on as lancet and pierces the skin/cuticle of the victim.
9. The retractor muscle (attached to the rear of the oblong plate and the front of the quadrate plate) then
acts antagonistically.
10. It is also attached to the quadrate plate and the oblong plate. As it contracts it attempts to pull the
sting out.The worker honeybee has a barbed sting so when she stings a mammal, the barbs become
embedded and the retractor acts to push the sting deeper into the tissues.
12. Each side of the stinging apparatus acts alternatively and in quick succession similar to blades of a
hedge trimmer each side alternatively contracting and relaxing.
13. As the honeybee worker cannot retract her sting she leaves it in the victim with its attachments
including the 7 th gangion, part of the anus and the whole sting apparatus including musculature which
means the venom continues to pump into the victim. The wounded worker honeybee subsequently dies.
14. A queens sting is slightly curved which may aid her stinging with her long abdomen, she has only
tiny barbs so can remove her barb and repetitively sting.
15. There are no muscles in the venom gland, venom sac or bulb of the sting. It is the action of the
lancets and their associated umbrella valves that pour the venom into the victim.
16. It is the combined pushing via the abdominal musculature, the muscles of the legs and those on the
plates of the sting that pushes the sting in place.
38
Q1 Name the valve at the anterior end of the ventriculus.
proventriculus
39
labellum/flabellum location
far end of glossA
40
pairs of spiracles
10 pairs
41
JH secreted by what organ
corpora allata
42
fat body cells found only in larva and pupa
urate
43
organ smaller in summer bees than winter bees
rectum
44
11 (a) Name the different types of eyes found in a worker bee and state the number of each
type and their location.
simple eye/ocelli
2. 3
3. on top of head (workers)
4. Compound
5. 2
6. on either side of the head
45
Describe the structure of a single ommatidium. 7 Marks
he light gathering parts:
1. Transparent corneal lens hexagon shaped
2. Crystalline cone made from 4 cone (accept semper) cells which are hard and transparent &
tapering at the end
3. Outside the crystalline cone are 2 primary pigment cells (cornegen cells) the purpose of
which is to prevent light from other ommatidia entering the come
The sensory parts:
4. Retinula cells which are elongated nerve cells 8 full length and 1 short all twisted around
each other
5. Rhabdom at the centre of retinula cells is a space filled by microvilli which are finger like
projections from the edges of the retinula cells
6. Secondary pigment cells surround the retinula cells
7. Nerve fibres pass from the end of the retinula cells
46
What is on the surface of the ommatidium and what function does that feature serve
Hairs on the edge
2. detect wind speed
3. helping bees assess flying distance
4. protection from damage
47
a) List the differences between winter bees and summer bees.
Summer bees
Live 5-6 weeks
2. Low levels of glycogen
3. High metabolic rate
4. Hardworking- work selves to death
5. Care for brood
6. Atrophied hypopharyngeal gland in
food older bees
7. Rectum voided frequently
Winter
1. Live up to 6 month. 2. can contain large amounts of glycogen protein and fat in fat bodies
3. Lower metabolic rate
4. Little work
5. Little brood rearing
6. Hypopharyngeal gland plump & full of brood
7. Rectum collects waste until it can be voided, enlarged
48
List the factors determining caste determination.
Eggs laid in worker/queen cell
2. white secretion = mandibular gland, clear= hypopharyngeal gland, yellow=crop content
(sugar and pollen)
3. Workers are fed brood food in the ratio 2:9:3 white/clear/yellow (derived from pollen) for
3 days
4. After day 3 the worker receives less white, more clear and more yellow
5. Queen fed royal jelly for 3 days
6. Royal jelly contains about 34% sugar and mainly mandibular gland secretions (white food)
7. Queen then fed food which is a ratio of 1:1white to clear for 2 days
8. Queen larva receive x10 as much food as worker brood, the higher feeding rate stimulates
stretch receptors of the ventriculus
9. Queen larva have a higher rate (x10 of worker brood) of Juvenile Hormone by day 3
10. this promotes queen characteristics by stimulating the corpora allata
49
List 6 functions of haemolymph.
Transport of food/waste and hormones
2. Mechanical support
3. Regulates/controls water contents of cells
4. Metabolism – chemical reactions take place in it and chemicals are broken down
5. Phagocytosis surround and destroy bacteria and parasites
6. Wound healing
7. Eversion of endophallus in drone
50
Name the 2 parts of haemolymph.
Plasma
2. Haemocytes
51
Describe how haemolymph circulates around the bee’s body.
Fluid underneath the ventral diaphragm is moved front to back
2. Fluid above the dorsal diaphragm is moved back to front
3. The heart muscles in the abdomen contract and squeeze haemolymph forward into the
aorta in thorax the muscles relax
4. 5 pairs ostia in the heart open and haemolymph flows in to fill the cavity
5. The aorta ends just behind the brain ensuring the brain is supplied
6. Antennal vesicle relaxes and haemolymph flows into it through an opening at the back
7. The antennal vesicle then squeezes fluid through the 2 vessels going into the antennae
52
Give an account of the development of the egg from the time it is laid to the point at
which the larva emerges from it.
Cleavage the nucleus divides forming cells which spread throughout the yolk
2. Blastoderm formation cleavage cells move to form the blastoderm which is immediately
inside the vitelline membrane
3. Germ band forms- blastoderm thickens on ventral side and forms germ band which
spreads over sides and end of egg
4. Germ band divides by longitudinal fissures and divides into 2 lateral plates at side and 1
median plate in the middle of ventral side
5. Median plate moves inwards towards yolk and becomes mesoderm
6. Lateral plates grow ventrally and join together to form ectoderm which surrounds
mesoderm
7. Endoderm forms as 2 ingrowths from front & back of blastoderm. They become separate
structures moving inwards then enclose the yolk – this will become the ventriculus
8. Ingrowths from ectoderm appear which will become the front and hind gut
9. Day 3 larva moves and bursts the membrane surrounding it - the amnion
53
List 3 differences between the endocrine and exocrine glands
Endocrine
ductless
hormones directly into haemolymph
affect individual bee
Exocrine
ducted
release pheromones outside of body
affect other bees
54
b). Name three of the glands making up the endocrine system in a larva, describe where they
are located and what they do.
Neurosecretory cells
2. In groups in brain and ganglia
3. Secrete chemicals to other glands or down nerve fibres to other organs
Corpora cardiaca
5. 2 glands behind brain either side of aorta
6. Store chemicals produced by neurosecretory cells and also make chemicals of their own
7. Corpora allata
8. Either side of oesophagus
9. Produce juvenile hormone
10. Prothoracic glands
11. 2 glands in thorax near first spiracle
12. Produce and secrete ecdysone
55
c) What endocrine gland is present in the larva but not in the adult bee and what does it
produce
Prothoracic
2. Ecdysone
56
Deescribe where the sting is located in an adult bee, the features forming the structure of
the sting and how these operate to inject venom into a victim.
The sting is housed in the sting chamber at the rear of the abdomen A7.
2. To activate the sting, the tip of the abdomen is swung down into an almost vertical
position.
3. The shaft which normally encloses the sting mechanism is swung upwards.
4. On each side the sting comprises of 3 main plates.
5. The lower plate, the oblong plate is fixed and does not move.
6. This plate is continuous with the 2nd ramus which arches backwards
7. to run continuously with the central rod of the bulb
8. and merge to form one common stylet.
9. The upper plate, the quadrate plate is mobile and is moved backwards and forwards by the
protractor and retractor muscles.
10. The triangular plate is continuous with the 1st ramus,
11. it is a long curved rod which arches backwards to run continuously with the lancet.
12. When the quadrate plate is pulled backwards the triangular plate rocks on the oblong
plate,
13. the movement transferred to the arching ramii causing retraction of the lancets.
14. Equally when the quadrate plate is pulled forwards by the protractor muscles the
triangular plate rocks forwards and the lancet is protracted.
15. The 1st ramus is grooved and runs on a track like ridge formed by the 2nd ramus.
16. The ramii enter the bulb and exit to form the two lancets and one stylet.
17. The track and groove of the stylet and lancets allow the two lancets to glide smoothly back
and forth.
18. The bulb is a sac like structure lying between the oblong plates and holds the venom
produced by the venom gland.
19. The venom is propelled down through the bulb by a structure attached to each lancet,
called the umbrella valve,
20. into a central canal formed by the two lancets and the stylet.
21. When a honey bee stings a soft bodied animal the backward facing barbs on the lancets are
stuck,
22. giving purchase for the other lancet to penetrate deeper into the wound.
57
Name 4 of the main components which are found in venom
Hyaluronidase
2. Phospholipase A
3. Phosphatase
4. Histamine
5. Melittin
58
List the source, purpose and the main component of the alarm pheromones produce by
the worker.
Mandibular gland
2. Subdue intruder
3. 2-Heptanone
4. Koschevnikov gland
5. attract other bees to the location and causes the other bees to behave defensively,
6. Iso-pentyl acitate
59
Briefly describe the central nervous system of the adult honeybee including
its constituent parts and their basic structure. (histological detail is not required)
Brain:
2. In 3 parts
3. Protocerebrum
4. Including optic lobes
5. And mushroom bodies (corpora pedunculata)
6. Deutocerebrum
7. Principally antennal lobes
8. Tritocerebrum
9. Connected to sub-oesophageal ganglion which is beneath oesophagus.
10. Ganglia:
11. 7 ganglia in total
12. 2 thoracic
13. 5 abdominal
14. Ventral nerve cord.
15. Double
16. Connecting brain and ganglia
60
) Write a brief account of Juvenile Hormone including its functions in the larva and
adult honeybee.
Produced by corpora allata
2. Either side of oesophagus
3. Part of endocrine (hormone) system
4. In larva and pupa high levels maintain larval characteristics
5. Fall prior to each moult
6. Works in this instance with ecdysone
7. Increases as JH falls.
8. In adult worker concerned with aging
9. And age polyethism
10. Low JH in house bees
11. High JH in foraging bee
12. Works antagonistically with vitellogenin
13. Major influence in caste differentiation
14. High levels of JH in queen larvae
15. Help determine queen characteristics
61
What is an enzyme?
aid with the catalyzation of a biochemical reaction
Enzymes are normally protein in nature and are involved in a diverse array of biological reactions from digestion to vision.
62
What is the role of sucrase?
Sucrase is a digestive enzyme to enable the catalyzation of sucrose (C12H24O12) into fructose (C6H12O6) and glucose (C6H12O6), and to aid in sugar metabolism and digestion
63
What are malpighian tubules and around how many are there in the adult bee and the larvae
Malpighian tubules filter the waste product by extracting waste products from the hemolymph. They produce uric granules and regulate water management (osmoregulation)There are around 100 in the adult bee but only 4 in the larvae.
64
What is the proventriculus and what is its function?
It is a valve that separates the crop from the ventriculus, it protrudes into the crop where it 4 triangular lips open and close to trap pollen. It is collected into pouches at the angles of the lips forcing nectar back into the crop, the bolus of pollen is then sent into the ventriculus.
65
What are spiracles and where are they situated?
Spiracles are openings in the bee's abdomen and thorax which allows the trachea to access oxygen and remove carbon dioxide.
66
How is oxygen transported in the bee?
It is transported via the tracheal system, i.e. from the exterior through a spiracle, via a trachea possibly though an air sac to another trachea , a smaller trachea etc. to a tracheole and eventually to a very fine tracheole close to the cell that requires it.
67
7. Where are the ostia found and how many are there?
The ostia are found in the heart. There are 5 pairs of ostia.
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8 b) Describe how pollen is ingested, digested and absorbed by the bee. Include the structure and function of the crop and ventriculus
b) Pollen is ingested by the bee using its mandibles and moves through the mouth and pharynx down the oesophagus by peristalsis or rhythmic muscle contraction. Once it enters the crop it becomes mixed with nectar and other contents, and portions of pollen are filtered and shaped by the proventriculus into a bolus. This pollen bolus then moves into the ventriculus for digestion, as it releases enzymes including protease to break down the protein in the pollen. In addition, the bolus is covered by a peritrophic membrane or jelly-like substance which protects the lining of the ventriculus from the abrasive coating of the pollen. Once the protein elements have been broken into amino acids they pass through the walls of the ventriculus and into the haemolymph, and are transported to cells for use. The undigestible parts of pollen move through the intestine into the rectum and after any water has been absorbed by the rectal pads they are expelled through the anus.
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The function of the honey crop
is primarily to allow the storage of quantities of nectar collected from the field, much of which may be regurgitated and stored in the hive (as opposed to being digested by the bee). Furthermore, it acts as a food ‘store’ for the bee itself, with that food being released to the gut, as required. It is also used to carry water back to the hive but not to store it.
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The structure of the honey crop
is that of a balloon-shaped bag. It has tense, thin walls, and can expand to hold up to ~100mg of nectar, collapsing to a flabby pouch when empty. It has the same fundamental structure as the oesophagus, and supports peristalsis via an initial layer of longitudinal muscles (closest to the internal cavity), and being surrounded by circular muscles to the outside. It has a folded cuticular lining allowing significant expansion and to protect it from the pollen grains.
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How is pollen digested
The pollen bolus will move through the ventriculus by means of peristalsis. Most digestion takes place here. The cellular lining of the ventriculus (the epithelium) has finger-like folds whose cells are always actively dividing and proliferating. These cells are charged with enzymes (proteases), which penetrate the pollen grains via their pores, and which digest their contents, breaking them down into proteins and amino acids, which are then absorbed through the ventricular lining back into the haemolymph.
Similarly, any fats in the pollen are broken down by the enzyme lipase, into fatty acids and glycerol and are similarly passed into the bloodstream.
Digestion occurs also (albeit to a lesser extent, but using a similar mechanism) as the pollen subsequently passes through the small intestine.
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The function of the ventriculus
is therefore the digestion of food via the action of enzymes.
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The structure of the ventriculus
the inner lining is of epithelium, thrown into folds which has mucous producing cells producing layers of peritrophic membrane . It also produces a variety of enzymes. The next layer is a circular muscle layer producing the annular like structure and external to this are longitudinal muscles. (Stell)
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How food is absorbed
Both the lining of the ventriculus and (to a lesser extent) the small intestine are structured with folds, which create a large surface area through which the products of digestion can be absorbed.
Proteins, amino acids and fatty acids can be absorbed firstly through the peritrohic membrane, then through this cell lining, into the haemolymph.
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8 c) What and where is the peritrophic membrane? What is its function?
What?
The peritrophic membrane is a jelly-like sheath, comprising ~10 gelatinous layers.
Where?
It is found along the length of the ventriculus, over the epithelium.
Function
It exists to ‘envelop’ the food passing through the ventriculus. Specifically, it is thought that it protects the delicate cell structures in the epithelial lining from damage which may otherwise arise from the passage of sharp/abrasive solids (i.e. rough walls of pollen cells). It permits the passage of the products of digestion to the epithelium, and therefore has a function in the digestive process. Furthermore, the membrane (in an adult bee) helps prevent the transfer of pathogens (e.g. paenibacillus larvae larvae (AFB)) into the gut lining.
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Describe the excretory system of the honeybee, including the functions of the Malpighian tubules and the rectal pads.
E-Malpighian tubules- join the ventriculus right before the pyloric valve and are closed at the other end. Act like kidneys by filtering out wastes. They are long and threadlike, composed of a single layer of cells. There are around 100 of them. Small muscles on the outside of the tubes move the tubules around in the haemolymph increasing the exposure to and mixing of the haemolymph to be filtered.( C. DAVIS, NB STELL disputes this) The lumen is surrounded by microvilli to increase the surface area so to allow reabsorption of required substances. They also actively secrete substances into the lumen. Both reabsorption and secretion require energy. They mainly remove nitrogenous waste resulting from the breakdown of excess proteins by filtering it out from the haemolymph and passing it down the lumen of the tubule to the ventriculus. Any useful substance like water is filtered back through the walls to the haemolymph.
* F-Rectal Pads- there are six, they reabsorb water from the rectum
* G-Rectum- stores wastes until the bee can eliminate when in flight outside hive. It can expand greatly to fill most of the abdomen of a winter bee.
* H-Small intestine- further absorption of water and nutrients
* Anus- not on diagram, but definitely part of the excretory system! Rectum is emptied through anus while bee is in flight.
* Carbon dioxide, water vapour and other metabolism waste products exit through the tracheoles, tracheae and spiracles.
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b) What is main nitrogenous waste product and from what is it derived?
Uric Acid-is created by the breakdown of proteins into amino acids, the catabolism of the amino acids creates uric acid which is excreted from the Malpighian tubules.
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Two types of waste products produced:
Carbon dioxide – removed by respiratory system.
Nitrogenous waste – removed by excretory system.
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4 attributes of the Excretory system:
Filtration of substances by the Malpighian Tubules
Reabsorption of useful substances back into the haemolymph, found in the excretory system.
Active secreting of substances from the haemolymph into the excretory system.
Removing the waste product externally from the body.
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Excretory process
There are around 100+ Malpighian Tubules floating freely in the haemolymph within the abdominal cavity. (like thin white cotton threads)
Each tube is built from a single layer single cell wall lining surrounding the lumen. They are attached to base of the ventriculus (hindgut) and the small intestine.
Substances in the haemolymph are filtered in the upper distal end of the tubules through passive filtering (non-discriminatory, so water may also pass through), and travels down the lumen (non-discriminatory)
As the substances pass down the lumen (proximal), some useful substances and water are reabsorbed into the haemolymph (such as salt if required).
Active secretion of other substances by other cells from the haemolymph also enter the tubules by pulling the passing molecules in.
The process of resorption and secretion requires a lot of energy – oxygen, so requires their own supply of tracheoles.
The waste product in the lumen is passed though the small intestine (possible reabsorption of water and salts into the haemolymph), and finally reaching the rectum.
The 6 rectal pads within the rectum are used for reabsorbing water and essential ions from the waste fluid, back into the haemolymph.
The waste is then expelled from the by through the anus.
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How does respiration differ between an active, flying bee and a bee at rest?
In an active flying bee the respiratory rate can reach up to 150 per minute. The flight muscles produce large amounts of carbon dioxide and require a large amount of oxygen.
This triggers the strong and continuous autonomic abdominal expansion and contraction.
The abdominal and the first thoracic spiracle are opened with abdominal expansion causing the abdominal air sacs to fill.
These then close and the contraction of the abdomen moves air out of the abdominal air sac to the abdominal organs and forward to the thorax where the air via the tracheal system. Air can be directed both forward or backward and the spent air expelled through the third spiracle mainly.
At rest bees have a low metabolic rate and the respiratory cycle with their abdominal muscle cycle is slow and gentle. Most of the inspiration and expiration occurs through the first thoracic spiracle but some expiration occurs through their abdominal spiracles allowing air flow mainly from the thorax to the abdomen.
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