Stabilizing Selection for Number and Pattern of Extra Bristles in Drosophila Melanogaster

Selection for ethanol tolerance was equally successful in two populations of D. melanogaster in both of which the frequency of AdhF was 0�5 at the start of the experiment.

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Stabilizing selection on individual pattern elements of aposematic signals

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.0926 ◽

2017 ◽

Vol 284 (1861) ◽

pp. 20170926 ◽

Cited By ~ 17

Author(s):

Anne E. Winters ◽

Naomi F. Green ◽

Nerida G. Wilson ◽

Martin J. How ◽

Mary J. Garson ◽

...

Keyword(s):

Pattern Analysis ◽

Marine Organism ◽

Warning Signal ◽

Colour Pattern ◽

Stabilizing Selection ◽

Warning Signals ◽

Fish Predator ◽

Selection For ◽

Aposematic Signals ◽

Behavioural Experiments

Warning signal variation is ubiquitous but paradoxical: low variability should aid recognition and learning by predators. However, spatial variability in the direction and strength of selection for individual elements of the warning signal may allow phenotypic variation for some components, but not others. Variation in selection may occur if predators only learn particular colour pattern components rather than the entire signal. Here, we used a nudibranch mollusc, Goniobranchus splendidus , which exhibits a conspicuous red spot/white body/yellow rim colour pattern, to test this hypothesis. We first demonstrated that secondary metabolites stored within the nudibranch were unpalatable to a marine organism. Using pattern analysis, we demonstrated that the yellow rim remained invariable within and between populations; however, red spots varied significantly in both colour and pattern. In behavioural experiments, a potential fish predator, Rhinecanthus aculeatus , used the presence of the yellow rims to recognize and avoid warning signals. Yellow rims remained stable in the presence of high genetic divergence among populations. We therefore suggest that how predators learn warning signals may cause stabilizing selection on individual colour pattern elements, and will thus have important implications on the evolution of warning signals.

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Social modulation of oogenesis and egg-laying in Drosophila melanogaster

10.1101/2021.09.13.460109 ◽

2021 ◽

Author(s):

Bailly Tiphaine ◽

Philip Kohlmeier ◽

Rampal Etienne ◽

Bregje Wertheim ◽

Jean-Christophe Billeter

Keyword(s):

Drosophila Melanogaster ◽

Social Context ◽

Social Systems ◽

Fruit Fly ◽

Egg Laying ◽

Physiological Adaptation ◽

Group Members ◽

Selection For ◽

Underlying Mechanisms ◽

Gravid Females

Being part of a group facilitates cooperation between group members, but also creates competition for limited resources. This conundrum is problematic for gravid females who benefit from being in a group, but whose future offspring may struggle for access to nutrition in larger groups. Females should thus modulate their reproductive output depending on their social context. Although social-context dependent modulation of reproduction is documented in a broad range of species, its underlying mechanisms and functions are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The tractability of the genetics of this species allows dissecting the mechanisms underlying physiological adaptation to their social context. Here, we show that females produce eggs increasingly faster as group size increases. By laying eggs faster in group than alone, females appear to reduce competition between offspring and increase their likelihood of survival. In addition, females in a group lay their eggs during the light phase of the day, while isolated females lay them during the night. We show that responses to the presence of others are determined by vision through the motion detection pathway and that flies from any sex, mating status or species can trigger these responses. The mechanisms of this modulation of egg-laying by group is connected to a lifting of the inhibition of light on oogenesis and egg-laying by stimulating hormonal pathways involving juvenile hormone. Because modulation of reproduction by social context is a hallmark of animals with higher levels of sociality, our findings represent a protosocial mechanism in a species considered solitary that may have been the target of selection for the evolution of more complex social systems.

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