Exam

Question 1

Q1 What is the phylogenetic position of your assigned species within the Class Mammalia

Answer 1

Class: Mammalia
Order: Eulipotyphla
Family: Soricidae
Genus: Crocidura
Species: Crocidura russula

Question 2

Q1 -What are the sister taxa of your assigned species at the level of species, genus, family, order, and class?

Answer 2

At the species level, it’s closest relative is Crocidura shantugensis (Kim, et al.,)

genus level, its closest relative is Myosoricinae, which are a subfamily of shrews(Dubey et al.,).
For family, its closest relative are the hedgehogs, Erinaceidae(Sato et al.,) ,

and Afrosoricida, which are south american shrews are the closest relative at the order level (Douady et al.,)

Question 3

Q1 -Is there fossil evidence of your assigned species, genus, family, and/or order and what does this evidence indicate?

Answer 3

Overall, there’s not much fossil evidence of my species because most fossils found have been in fragments (Dubey et al.,) . That said, the study by Cornette et al., used geometric morphometrics to assign broken fossil fragments to species. They found more evidence that C.russula is more abundant in dry than humid habitats. (Dubey et al., used DNA markers to study the divergence of Crocidura russula colonization events. He found that the shrew divergence in Europe most likely came from one shrew crossing africa, and the divergence between eastern and western greater white-toothed shrews happened 2.25mya.

Question 4

Q2 What is the dental formula of your assigned species

Answer 4

I3/1. C1/1, P1/1, M3/3 =28

Question 5

Q2

-How is your assigned species’ dentition reflective of its phylogenetic position?

Answer 5

For one, all it’s closest relatives from the order Eulipotyphla all have the same four teeth types; incisors, canines, premolars, and molars. (Voyta et al.,) As well, they all contain a large number of teeth that are specialized for their insect heavy diet (Voyta et al.,).

Question 6

-How is the dentition of your assigned species reflective of its diet and the connection between form and function?

Answer 6

As insectivores, they need specialized teeth in order to feed. Conical incisors are adapted for grasping, Their teeth have tall sharp cusps that aid in piercing through invertebrate cuticles. As well, the cheek teeth works like shearing blades allowing shrews to crush their prey(Voyta et al.,).

Question 7

Q3 How does the hair of your assigned species work?

Answer 7

Shrews have short, intertwined hairs as opposed to long hair. This allows the hair to move in both directions without causing friction, something necessary for shrews as they navigate in narrow burrows. As well, some hypothesize the short intertwined hairs aid in waterproofing the shrew, as it traps tiny air bubbles(Williams).

Question 8

Q3 How does its hair develop?

Answer 8

I found no articles for hair development for crocidurinae but, for other insectivores such as moles this is what I found.,
During gestation, hair follicles are present 21 days post coitus. 17 days after birth, hair is very short and present all over. By day 27, the hair is perpendicular to skin and long. (Barrionuevo et al.,)

Question 9

Q3 how did its hair evolve

Answer 9

They evolved specialized vibrissae …

Question 10

Q3What is its hair for?

Answer 10

There’s two layers of hair; the underhair and protective hair with cuticle scales(Smith).
Waterproofing and aiding in movement
They use vibrassae as sensory organs for navigation and prey sensing (Catania)

Question 11

Q4 What is the audible frequency range and tuning of your assigned species?

Answer 11

Simeonovska-Nikolova found the dominant frequency was 10.7+- 0.05 kHz with a duration of 104. 2±4.4 ms. for chirping notes (DF=4.8±0.2 kHz, DU=23.5±1.1 ms). While clustering and huddling up to the partner, the animals produced calls consisting of short notes with a very low intensity (DF=1.0±0.07 kHz, DU=35.2±0.8 ms).

Question 12

Q4 What kind of pinnae does your assigned species have?

Answer 12

Zaytseva et al., observed that crocidura lack a boney bullae, that other mammals have, instead the tympanic cavity rostral to the cochlea is separated from the cranial cavity by a thin layer of fibrous tissue, and the ectotympanic bone, which supports the tympanic membrane, takes the form of an incomplete ring which is not fused to the surrounding bones. The chochela forms a short coil, and semicircular canal lies in a plane approximately perpendicular to the ectotympanic bone(Zaytseva et al.)

Question 13

Q4 How does your assigned species use its auditory system?

Answer 13

Shrews in general may use the echoes and reverberations of their calls for identifying routes through their habitat or for probing habitat type. (Siemers)

Another share: eight call types, all within the human audible frequency range (<20 kHz): short and long low-frequency squeaks with nearly flat contour, high-frequency squeaks with modulated contour, high-frequency squeaks with fractured contour, short screeches and screeches, clicks and whimpers ((Zaytseva et al.)

Question 14

Q4 What kind of vocalizations does your assigned species use and why?

Answer 14

threatening sounds, emitted in agonistic encounters, allow shrews to avoid conflicts, while those, emitted when clustering and huddling up to the partner, contribute to maintenance of group cohesiveness. The variability of frequency ranges and intensity of sounds probably reflects the territorial and sociable behaviour(Simeonovska-Nikolova).

Question 15

Q5 What is the shape and characteristics of the nose, nostrils, and nasal cavity of your assigned species?

Answer 15

the glenoid region of the squamosum is tightly attached to the nasal capsule whereas in other mammals its attached to the otic capsule or petrosal.(Maier et al.,)

Question 16

Q5 How does your assigned species use olfaction, scents, and chemical communication?

Answer 16

Olfaction is the primary means of communication for insectivores as it is the most efficient form of communication below the surface, and for animals with high basal metabolism, such as shrews. Shrews possess scent glands that they use for inter and intraspecific communication. (Stephan et al.,)

Question 17

Q5 Is the vomeronasal system important to your assigned species?

Answer 17

For insectivores, the vomeronasal system seems to play a role in sexual communication, though within insectivora, some species have a highly developed vomeronasal system while others have small ones.(Stephan et al.,)

Question 18

Q6 Does your assigned species have a slow or fast metabolism?

Answer 18

Slow for shrews, but fast overall…We found that mass specific energy expenditure amounted to 133.40T12.48 J g1 h1 for C. russula and 329.99T38.05 J g1 h1 for S. etruscus(Magnanou et al.,)
All shrews have a higher metabolic rate than what would be expected for mammals of such a small size (Magnanou et al.,). However, Crocidurinae have much slower metabolix rates (132% of the expected value) whereas soricidae have 315% of the expected value for mammals of the same size. This difference may be due to adaptation to different climates and reproductive strategies.(Magnanou et al.,)

Question 19

Q6 What is your assigned species thermal neutral zone and thermal conductance?

Answer 19

Small mammals, like crocidura russula are unable to increase their fur length to reduce thermal conductance. Instead, they increase Vo2 to improve their cold tolerance. As well, temperate shrews like crocidura russula have a more reduced thermal conductance than tropical species allowing them to reduce energetic costs to thermoregulate. (Sparti)

Question 20

Q6 What are some key phylogenetic, environmental, and dietary factors affecting the thermal biology and metabolic ecology of your assigned species?

Answer 20

In a study by Oliveira et al., observed that behaviors that increase access to resources or consume energy, such as boldness and locomotion, are positively related to RMR. They also concluded that the energetic strategy for C.russula depends on its environment (rural or urban) and observational context.

Question 21

Q7 What is the body size (mass and length) of your assigned species and how does this compare to the size of other members of its genus, family, order, and class?

Answer 21

Before ireland invasion 11.45 + 0.25 g; length: 117.73 + 0.56 mm) when compared to shrews sampled ‘after’ the invasion (weight: 10.58 + 0.17 g; length: 114.73 + 0.44 mm; p < 0.0001) and when compared to Belle Île C. russula (weight: 9.84 + 0.2 g; length: 111.81 + 0.78 mm; p < 0.002; Table S2; Figs. 2B and S2) (Browett et al.,)
Females with litter weighed around, 14g, species collected for study ranged 10-15 g(Genoud and Perrin)
It falls in the middle compared to other shrews. Some Members of the sorex family weigh 3.6g others 18g! (Morrison et al.,)

Question 22

Q7 How is the physiology, behaviour, and life history of your assigned species typical and/or atypical for a mammal of this body size?

Answer 22

Short life span-typical Small body- typical(Speakman)
Fast metabolism (prev qs) is atypical since its so small

small mammals have more offspring- typical C russula Have 5 offspring per litter on average, ranges 1-10, breed march-august sometimes october, lifespan is short (under 2 years) and they reproduce 2-4 times in their lifetime (Genoud and Perrin)

Question 23

Q7 What is known about intra-specific and developmental allometries within your assigned species?

Answer 23

greatest growth rates body weight at the interval weeks 0-14 , peaking at fourteen weeks of age.
High growth rate of EL(ear length) in following weeks, body weight increases 8-18 months.
Individuals born earlier in the breeding season grow faster than those born at the end, which explains the fluctuations observed in mean HBL (head and body length) from class 2 june-onwards (López-Fuster and Ventura).

Question 24

Q8 -What is the diet of your assigned species?

Answer 24

Brahmi et al., conducted a diet analysis of crocidura russula. They found 83% of specimens were insects. The remainder were plants, arachnids, centipedes, and geckos. Most prey are small with a mode at 3mm size, though sometimes animals over 10mm are also preyed. However, this diet is different from the invasive populations in europe, and within europe their diet may shift depending on the area, indicating that C russula is an opportunistic insectivore.

Question 25

Q8 How is the headgut, foregut, midgut, and hindgut of your assigned species reflective of its diet?

-What are some other ways that the truism ‘you are what you eat’ apply to your assigned species?

Answer 25

C russula have a simple, short gastronomical track. They do not contain a caecum, which leads to no division between the small and large intestine. Typically, simple gastronomical morphology is related to the high digestibility of their food. Herbivores have much longer large intestines and gut length than carnivores and omnivores due to the long time it takes to digest plant material.Thus, since crocidura russula is an insectivore, it’d be expected that its GIT is more similar to that of carnivores than herbivores,which it is. As well, short GIT reduces energetic costs which is very important for Crocidura russula as its active both in the day and night, which is not true for all shrews. As well, another adaptation of a short GIT is that the decrease storage capacity of food will aid its climbing habitat.Since the GIT is so short, in order to insure fast food absorption, villi are present on the longitudinal colonic mucosal folds. (Boonzaier et al.,)

Question 26

Q9 -Quantify key life history traits of your assigned species

Answer 26

Have 5 offspring per litter on average, ranges 1-10, breed march to august sometimes october, lifespan is short (under 2 years) and they reproduce 2-4 times in their lifetime (Genoud and Perrin)

Question 27

Q9 -How do the life history traits of your assigned species reflect trade-offs between survival and reproduction?

Answer 27

Low survival/lifespan but reproduce a lot! (5 months breeding season) so energetically costly but they have a short life span so producing offspring is a good tradeoff (Genoud and Perrin)

Question 28

Q9 -How is the life history of your assigned species interrelated with its metabolism, body size, and diet?

Answer 28

Short GIT allows fast digestion thus saving energy which can then be used for thermoregulation during winter, or higher reproductive success, or greater parental care. Fast metabolism also allows greater reproductive success

Question 29

Q10 -Is your assigned species solitary or group- living?

Answer 29

Crocidura russula is both solitary and group living depending on the season. During winter, they live together, sharing 52% of their homerange (52% overlap). During the breeding season the females become more territorial, and share their nests only with one male. (Cantoni & Vogel)

Question 30

Q10 What costs and benefits of group living - particular to your assigned species - account for its social structure?
Benefit: lots of offspring & mating opportunities.
Benefit: C russula saves 30% of energy expenditure during the winter by use or torpor and group huddling (Genoud)
Cost: Monogamous so less genetic diversity (they breed so much!)
Cost: individuals born early on face the risk of breeding with mother, leading to low genetic diversity ((Balloux et al., and another source is better i forget which…)
Cost: If too many individuals are huddled together during winter, its population budgets may get too high (3000jk / ha*day) and cause population stress (Genoud)
Cost: Offspring born later only reproduce the following year…
Cost: energetically costly??

Answer 30

Benefit: lots of offspring & mating opportunities.
Benefit: C russula saves 30% of energy expenditure during the winter by use or torpor and group huddling (Genoud)
Cost: Monogamous so less genetic diversity (they breed so much!)
Cost: individuals born early on face the risk of breeding with mother, leading to low genetic diversity ((Balloux et al., and another source is better i forget which…)
Cost: If too many individuals are huddled together during winter, its population budgets may get too high (3000jk / ha*day) and cause population stress (Genoud)
Cost: Offspring born later only reproduce the following year…
Cost: energetically costly??

Question 31

Q10 What is the mating system of your assigned species and how does this relate to its general social organization?

Answer 31

C russula are monogamous(Balloux et al.,), something not often seen in mammals. This makes sense then that females become territorial allowing only one male in their burrow during the breeding seasons.

Question 32

Q10 What are some examples of cooperative, selfish, altruistic, and/or spiteful behavior expressed by your assigned species?

Answer 32

Cooperative- nest sharing
Selfish- territorial females

Question 33

Q11 Does your assigned species (or its genus, family, or order) have a smaller or larger brain size than expected given its body size and what are some factors that might explain this degree of encephalization?

Answer 33

Between crocidurinae and soricinae, crocidurinae on average have smaller brains. In the study that compared these two, C russula had one of the smallest brain weight among the other 5 species of crocidura measured, and its brain components weighed less as well. (brain weight =188 mg).(Stephan et al.,)
What may explain this is due to evolution. In primates, neocortex and striatum are the most progressive components in brain development, and these two parts are what differs most between crocidurinae and soricinae. Possibly Their larger relative size in Soricidae points to a higher evolutionary level reached by recent representatives of this subfamily.(Stephan et al.,)

Question 34

Q11 How is brain size of your assigned species (or its genus, family, or order) inter-related with its metabolic rate, diet, life history, and social organization?

Answer 34

A study done by Barton et al., showed that nocturnal mammals tend to have larger olfactory structures than diurnal/ partly diurnal mammals (C russula is partly diurnal)

Question 35

Q11 -Is there anything unusual or specialized about brain form and/or function in your assigned species (or its genus, family, or order)?

Answer 35

based on a number of morphological traits, Crocidurinae are more primitive than Soricinae though this study does not but there’s some evolutionary things thats better in crocidurinae despite it being overall more primitive brain; read the last paragraph of (Stephan et al.,) for example; slower metabolic rate than soriinae, crocidurinae have unsually high populations and are less territorial, (in primates, bigger brain= need more space

While larger-brained species have numerous cortical subdivisions allowing for specialization of functions, shrews may compensate for their fewer areas with high connectivity and short conduction times, possibly resulting in more efficient local networks. (Catania)

Question 36

Q12 What is the conservation status of your assigned species?

Answer 36

C russula is not endangered and infact is an invasive species to ireland since 2007 . expansion rate of 5.5 km/yr (McDevitt et al.,)

Question 37

Q 12 What are some species traits that contribute to this status?

Answer 37

There are no other shrews in ireland except for one, of which C russula and it share diet and habitat preferences, and C russula is larger than the other shrew. Overall C russula is spreasding quicker than native shrew in Ireland,
possibly due to long breeding period. Typically only the first litter is able to reproduce the following year but with mammals in new areas, breeding patterns may change intraspecific competition is less intensive. Hypothesized then that they reach sexual maturity quicker thus allowing them to expand quickly (McDevitt et al.,)

For mediterranean populations, they are not endangered however, habitat types shape population dynamics. C. russula experiences its greatest population growth in open habitats, thus protecting these areas would help maintain C russula at its healthy population size/conservation status (Torre et al.,)

Question 38

Q12 How do humans impact your assigned species and how does your assigned species impact humans?

Answer 38

Human-assisted dispersal may also be involved because C russula occupy farms and human establishments, which may lead to their dispersal via transport of livestock or produce, whereas the native shrew does not associate itself with humans. (McDevitt et al.,)

Question 39

Q12 What are some critical knowledge gaps that must be filled and/or conservation actions that must be taken to ensure the long-term survival of your assigned species?

Answer 39

Protection of open habitats Torre et al.,
future research should focus further on the direct interactions and resource utilization between C. russula and S. minutus in Ireland. More studies would also be desirable on the potential cumulative impacts of the two invasives, C. russula and M. glareolus [24], exploiting the fact that C. russula has recently become established outside of the range of M. glareolus (outlier population ‘O1’; Fig. 1A).McDevitt et al.,)