In this order, Odonata's evolution of sexual traits is mistaken as a result of male-male completion. But females do contribute these traits, very evidently in Damselflies due to the harrasment they face. This presentation is about the evolution and ethology of male avoidance by females color polymorphism, its inheritance, and consequences.

1. Seminar IV

2. Polymorphism
Presence of different morphological forms
Multiple benefits
 Division of labour
 Predator avoidance
 Sexual dimorphism – attract mate
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3. Sex limited polymorphism
Either male or female are polymorphic
Polymorphic male: male-male competition
Polymorphic female
Against visual hunting predator
Sexual harassment by males
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4. Sex limited polymorphism
in insect societies
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(Baral et al., 2019)

5. Distribution of Polymorphism across Odonata
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(Fincke, 2004)
Larger size
On flight
Detects females
by motion
detector neurons

6. Love is in air ???? Damselflies
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8. Female harassment
Male with strong claspers
Repeated copulation- damage female’s
 wings
 reproductive tract
 reduce fitness
Dominant males remove sperm and egg fertilization results from
the female reproductive tract and re-copulate
(Fleming, 2019)
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9. Female strategies to overcome this….
Evolved monogamy (Fincke, 1986)
Pretend laying eggs even if she is not (Aguilar, 2015)
Shift in the activity periods compared to males (Pérez et al., 2021)
Allows sneaky males (Fleming, 2019)
Multiple colour morphs
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10. Multiple female colour morphs
Males easily recognize females - similar coloration
 Distracted & confused - multiple phenotypes or colour morphs
coexist
 Evolution of male mimicry – male like females - andromorphs
Escape from male harassment
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Learning by male ???

11. Ischnura elegans
 Reproductive season: May – September
(↑ in June)
Scramble mate competition
Males are best at locating females
Females - highest reproductive success
Male mate competition – intense
Female suffer high harassment
Half of male in a population never
succeed in mating
 Monomorphic male and 3 coloured female
morphs
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(Hammers and Gossum, 2008)

12. Colour polymorphism in
Ischnura elegans
3 coloured female morphs
Androchrome – male like female
– similar colouration & body melanin patterning
Gynochrome – ordinary female – 2 types
Infuscans - body melanin patterning similar to male
Infuscans-obsolete –lack black numeral stripes on thorax
Extent of male mimicry: Androchrome > infuscans > Infuscans-obsolete
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(Hammers and Gossum, 2008)

13. Androchrome frequency:
27-76%
↑sed towards North &
West
Male : female
male density
↑ Fandromorph - ↓ sed temp.
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(Hammers and Gossum, 2008)
W
30 populations – different water body
June: 16.0-16.5℃, 16.5-17.0℃, 17.0-17.5℃, 17.5-18.0℃
NS fandromorph

14. Mating attempts
Infuscans-obsolete
↓
infuscans
↓
Androchromes
↓ with ↑ similarity to males
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Extent of male mimicry: Androchromes > infuscans > Infuscans-obsolete
(Hammers and Gossum, 2008)

15. Andromorphs escapes from both conspecific
and heterospecific mating and thus harassment
(Svensson et al., 2007)
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Male like female suffer less from harassment

16. Stable morph differences in mating
rates across years and populations
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(Gosden & Svensson, 2009)

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What if these population are with low density of
andromorph which cannot be detected by males ?
Do males switch their preference for andromorphs
if their density increase in populations ?
1
2

18. Male clasping damage
 Non-androchromes: ↑sed number
of male claspings with increasing
density
 Androchromes lower sensitivity to
male clasping as their density
increases
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(Gosden & Svensson, 2009)
Circles: androchromes
Downward triangles: infuscans triangles
Forward triangles: infuscans-obsolete

19. Androchromes were not preferred by males
even if they are the majority morph
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infuscans-obsolete
Population with 85% androchromes
Males behaved indiscriminately and did not prefer the commonest androchromes
Diagonals indicates the expected proportion females mate to their population frequency
Points below the diagonal for female frequencies below 50% and above the diagonal
Androchromes infuscans
(Rivera and Guillen, 2007)
Androchrome mating is not density dependent

20. What if these colour morphs are
just age dependent colouration ???
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21. Inheritance of female polymorphism
in Ischnura graellsii
Polymorphism begins at teneral stage
- genetically distinct female types
- not just age related morphs
Inheritance – sex linked expression
-one autosomal locus
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(Cordero, 1990)

22. Laboratory matings – F1
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(Cordero, 1990)
A female produce – either of 1,2 or all three morphs
2 phenotypes – 1:1 or 3:1
3 phenotypes – 1:1 or 2:1:1 (A:I:O)
Males- 6 genotypes one phenotype
A- recessive
I- heterozygotes
O- dominant

23. Evolution of female colour morphs
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(Blow et al., 2021)

24. Ancestrally FM(H), P = 81%
All FP(T) - common ancestor FP(T),
derived from FP(D)
-high mating duration – Third morph
Two evolutionary transitions occurred
FM(H) → FP(D) → FM(A) & FM(T)
convergent evolution of 2 morphs
- intensity harassment & need of FP
Male mimicry and FP - derived traits
and not ancestral
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(Blow et al., 2021)
- monomorphic
- heteromorphic / gynomorphic
- dimorphic
- trimorphic

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 All island-endemic species are monomorphic – so the ancestors
 Species distributed widely - either FP(D) or FP(T)- adaptations for survival
 P(FP) ↑* ~5% with its geographic size range of 1 x106 km2
(Blow et al., 2021)
 FP is a trait having ancestry of years together
 Neither just a random morph nor a age dependent colouration
 A trait regulated by recessive genes
 Tri-allelic single autosomal locus regulating the inheritance

26. Why nature should support such a female
morph which even avoid the transfer its gene
to generations ??
Only Male harassment ??
Other fitness benefits ??
Does environment has any role to play in this
hide and seek of polymorphism ???
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27. Androchromes need not to hide
(Castillo- Pérez et al., 2021)
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Clear andromorphs – high temperature tolerant
Darker gynomorphs – heats up quickly, activity seizes at
high temp. where males are active
Adult male Andromorph Gynomorph
Ischnura denticollis

28. High temperature tolerance
Clear females – andromorphs
Dark females – gynomorphs
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(Castillo-Pérez et al., 2021)
(Cooper, 2008)

29. High elevation survival
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 High-elevation populations - sexually monomorphic and red
 low-elevation - sexually dimorphic with green females
(Cooper, 2008)
Megalagrion calliphya
Males
Andromorphs

30. Mean Anti oxidant breakdown time
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 Andromorphs break down hydrogen peroxide more effectively than gynomorphs
 Red pigmentation function on antioxidant & protects from UV damage
(Cooper, 2008)

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Evolution of male mimics gains
multiple benefits apart from “escape”
What about males? Does he bother
about these female games” ??

32. Males’ perspective
Q1-Andromorph
Q2,Q3- heteromorphs
A, B, C- male criteria's
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(Fincke, 2004)
Vm- cost of miss
Um- cost of false alarm
Umdis- cost on conspecific males
OSR – Operational Sex Ratio
 Cost of miss – selective force - evolve male learning
 At the cost of false alarm – wastage of sperms, time, energy
physical damage
Other side of the coin- FP in Males’
perspective

33. Female are the decision makers-playing
with their detectability
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(Fincke, 2004)
Females are the dictators of male fitness

34. Summery
Damselflies - polymorphic females
Evolved to overcome sexual harassment by males
FP are not density dependant
 Polymorphic female are distinct phenotypes – not just age
related morphs
It’s a derived trait, not ancestral
Andromorphs – high fitness compared to gynomorphs
Derives multiple benefits
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35. Conclusion
 Damsels- assumed as taxa whose females have reduced or no
control of mating and fertilization decisions
 Evolution and maintenance of secondary sexual traits is mainly
driven via male–male competition
 Contrary to this, “dull coloured” gynomorphic female face
harassment, hence have evolved bright andromorphs
 How exactly this number is maintained over generation- yet to be
solved by further studies
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