Females more promiscuous in colder climates

Now that I have your attention, a study into the behaviour of fruit flies has found females of the species Drosophila pseudoobscura have more sexual partners when they live in colder climates and are happier being monogamous when it is hotter. Researchers also found that some females are genetically programmed to have a large number of mates and will do so whatever the weather, while others will consistently stick to one mate.

A more appropriate term for promiscuity is 'polyandry'.

 

Temperature can shape a cline in polyandry, but only genetic variation can sustain it over time

Abstract

Multiple mating by females (polyandry) is a widespread behavior occurring in diverse taxa, species, and populations. Polyandry can also vary widely within species, and individual populations, so that both monandrous and polyandrous females occur together. Genetic differences can explain some of this intraspecific variation in polyandry, but environmental factors are also likely to play a role. One environmental factor that influences many fundamental biological processes is temperature. Higher temperatures have been shown to directly increase remating in laboratory studies of insects. In the longer term, high temperature could also help to drive the evolution of larger-scale patterns of behavior by changing the context-dependent balance of costs and benefits of polyandry across environments. We examined the relative influence of rearing and mating temperatures on female remating in populations of Drosophila pseudoobscura that show a latitudinal cline in polyandry in nature, using a range of ecologically relevant temperatures. We found that females of all genotypes remated more at cooler temperatures, which fits with the observation of higher average frequencies of polyandry at higher latitudes in this species. However, the impact of temperature was outweighed by the strong genetic control of remating in females in this species. It is likely that genetic factors provide the primary explanation for the latitudinal cline in polyandry in this species.

Experimental design to examine the effects of rearing and mating temperatures on female remating in 2 geographical populations of Drosophila pseudoobscura (Taylor et al. 2015).

Experimental design to examine the effects of rearing and mating temperatures on female remating in 2 geographical populations of Drosophila pseudoobscura (Taylor et al. 2015).

Source Science Daily.

Citation Michelle L. Taylor, Tom A.R. Price, Alison Skeats, and Nina Wedell, Temperature can shape a cline in polyandry, but only genetic variation can sustain it over time, Behavioral Ecology, first published online October 25 2015, doi:10.1093/beheco/arv172.