Lecture 8- Reptiles 5 (Social life) Flashcards Preview

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Flashcards in Lecture 8- Reptiles 5 (Social life) Deck (27):
1

What is the following in the visual, auditory and olfactory signals?

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2

What are the visual signals in jacky dragons?

-tail flick attracts attention -must be conspicuous against moving vegetation -works best when longer lasting -Signal duration in calm vs windy vegetation?

3

What about colour signals in lizards?

-can see UV so what looks to us as one colour will be more to them -eg, ornate dragons, on the bottom of their belly they have markings, males= we can see, females= can't see as it is two types of white (UV and normal), in an experiment it's been shown that males prefer females with more UV

4

What are some examples of vocal signals in reptiles?

-gecko vocalisation -purpose varies with species -the use in Diplodactylus damaeus = serve as aggression between males, try to bite, rape etc. -Gehyra variegata= protection against predators -Hemidactlyus frenatus= the clicking sound ttttt -use the calls in territorial disputes -when they eat an insect -male to female interactions, many other social situations

5

How do olfactory signals work in reptiles? How do they smell?

-tongue collects chemicals -deposits chemicals in the vomeronasal (Jacobsen's) organs -these organs are lined with nerve endings that lead to accessory olfactory lobe of the brain -most reptiles use olfactory cues -femoral pores= release chemicals through the bottom of their leggs= used as territorial markers

6

What is the predominant social behaviour in reptiles?

-solitary -polygamous -no parental care

7

Which groups differ in their social life and how?

-Social behaviour has evolved independently in numerous reptile groups (e.g. skinks, geckos, snakes) - Aggregation -Rudimentary parental care -Stable social groups

8

What is special about the Egernia group?

-approx 30 species, long lived and many of them show complex social behaviour

9

What types of social behaviour do the Egernia group lizards exhibit?

-stable social groups -social monogamy (throughout their lives, between breeding seasons)= the genetic father not necessarily the social one -family groups(as they are all live bearers and the juveniles stay with parents= delayed juvenile dispersal) -rudimentary parental care

10

What is the social structure in White's skink?

-71% groups consist of pair (29% social groups with >1 adult female) -Stable pair bonds (approx. 75% with same partner following season) -39% of social groups with one or more juveniles or sub-adults -Juveniles/sub-adults were the genetic offspring of the resident pair (75% of cases) -Extra-pair paternity (34%) (another father)

11

How big do the groups get in skink species?

-Egernia whitii (2-6 individuals) -Egernia stokesii (up to 17 individuals) -Egernia saxatilis (up to 14 individuals but usually ‘nuclear families’) -Egernia cunninghamii (up to 26 individuals)

12

What is sociality facilitated by?

-Recognition of individuals, -Recognition of familiar/unfamiliar individuals (recognition of group or non group members) -Recognition of related/unrelated individuals

13

Can White's skinks recognize their kin?

-measured the home ranges of individuals, the male one did not include the social offspring, only the genetic offspring -Males do not tolerate offspring of other males in their home range -Indirect evidence for kin recognition

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14

How did they determine kin recognition in tree skinks?

-using the chemicals released from the femoral pores and their poo (scats) -put paper towels with the chemicals and then the poo and measured how much time they spent investigating the smell -with paper towel= more time spent investigating non-self smells and more time spent investigating distantly related than closely related -the poo= more time on non-self smells but no distinction between close or distant relatives= so can't tell the kin by poo smell but can by the femoral pore chemicals

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15

How did they test the kin recognition in tree skinks using basking time and aggressive acts?

-more time spent basking with closely related than distantly related

-more aggression towards distantly related individuals then closely related

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16

What are scat piles used as?

-often used as territorial markers (Some Egernia species scat pile)

17

How did they test if scat piling is used for individual/group/species recognition?

-2 species types of skinks, tree skink(scat piles) and desert skink (doesn't scat pile)

-3 pieces to test= self (own poo), heterospecific (poo of different species) and unfamiliar specific (member of the same species= but haven't met)

-RESULTS:more time investigating unfamiliar smells than their own but no difference between the same species or different species= support theory that they can't tell the diff from poo

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18

How did they test the recognition of group vs non-group individuals in gidgee skinks?

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-using both scats and paper towels with the femoral pore chemcials

-self, group member and non-group member poo and chemical

-RESULT: same for paper towels and poo -same result for related and unrelated group= therefore the main thing is if they are both in one group

 

-to test this further they put the chemicals and scats of related in group and related out of group to test if it were genetically affected.

-RESULT: can't distinguish related and unrelated= it is the group or ougroup that matters!

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19

What are the costs of sociality?

-Increased competition for resources -Increased probability of detection by predators -Increased transfer of disease and parasites

20

What are the benefits of sociality?

-Increased vigilance -Physiological benefits (e.g. reduced heat or water loss= huddling reduces this) -Parental care/protection

21

How is vigilance in gidgee skinks influenced by being a part of a group?

-much more time spent in non-vigilant behaviour when in group then when alone

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22

How do you measure vigilance in reptiles?

-walk towards them and when they fled= what distance where they away from you

23

What was the experiment about juvenile aggression towards juveniles in black rock skinks?

- High aggression to juveniles, particularly when unrelated

-much higher aggression towards juveniles who are unrelated

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24

What suggests that parental care protects against adult aggression in black rock skinks?

-the aggression directed at juveniles who are in the presence of their mother is much lower than when they are with unrelated adult/adults

-the aggression can result in death so by parental care the parents are ensuring higher survival rate for their offspring

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25

What are the factors in evolution of sociality? Why does it happen?

-Ecological factors promoting sociality -----Aggregation occurs when access to key resources (e.g. shelters, food) is limited because they are clumped in space or time ----Limited resources can favour the evolution of territoriality and social groups -Life-history traits promoting sociality ------Long life span and long period until reproductive maturity may favour delayed offspring dispersal

26

What is the evidence for the factors involved in the evolution of sociality?

-Within species, variation in habitat (e.g. E. striolata) is correlated with social behavior and aggregation -But evidence for the importance of ecological factors in explaining variation in sociality between species is mixed -All species examined so far are long lived and have delayed juvenile dispersal so the role of life-history is difficult to assess

27

Who can tree skinks, black skinks and gidgee skinks recognize?

-Tree skinks appear to recognise related individuals, but gidgee skinks and black rock skinks are mainly able to distinguish familiar/unfamiliar individuals irrespective of relatedness.