Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time.Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high-and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection.

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Many organisms, including humans, find symmetry more attractive than asymmetry. Is this bias towards symmetry simply a by-product of their detection system? We examined female preference for symmetry of the pigment pattern vertical bars in the swordtail fishes Xiphophorus cortezi and Xiphophorus malinche . We found a relationship between preference for symmetry and female size, with larger and thus older females spending significantly more time with the asymmetrical video animation as compared to the symmetrical video animation. The preference for asymmetry we report demonstrates that even if females can detect symmetrical males better, this does not preclude subsequent selection on females to prefer symmetrical or asymmetrical males. In addition, because the preference was correlated with female size, past studies may have missed preference for either asymmetry and/or symmetry by not examining the relationship between female preference and size/age or by measuring a limited size/age distribution of females. In both of the species of swordtail fishes examined, a high proportion of males are asymmetrical by more than one bar. We suggest that female preference may be maintaining fluctuating asymmetries in these fishes.

Summary 1.Females from many species assess fluctuating asymmetry (FA; nondirectional deviations from symmetry in bilateral traits) when choosing mates. However, the hypothesis that FA indicates the quality of a potential mate is controversial because of the lack of consistent evidence that FA is conditional or heritable. 2. We present evidence that FA provides information about growth rate in the swordtail fish Xiphophorus multilineatus, and a model for how variation in growth strategies could obscure the relationship between FA and stress. 3. Males from one of the genetically influenced size classes of males in this species (Y-II) are more often asymmetrical for the sexually selected trait vertical bars. We also detected a significant relationship between the absolute difference in otolith ring counts and absolute difference in vertical bar number, supporting the hypothesis that FA in vertical bars indicates developmentally instability. 4. In a diet manipulation study, we found support for an alternative growth strategy and a relationship between growth and FA. The Y-II males that grew faster on a high-quality diet had a relationship between higher growth rates and asymmetry that was not detected in the other genotypes. 5. Our results suggest a hypothesis to explain why FA does not always increase with stress: differences across genotypes in the threshold for environmental stress needed to shift the allocation of resources from growth to developmental quality will obscure the relationship between FA and environmental stress. Our results also provide an explanation for why the larger females of some species of swordtails have been shown to prefer asymmetry: in some conditions, choosing a mate that optimizes growth rate over developmental stability (asymmetry) may be adaptive.

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Despite decades of research on lobster species’ biology, ecology, and microbiology, there are still unresolved questions about the microbial communities which associate in or on lobsters under healthy or diseased states, microbial acquisition, as well as microbial transmission between lobsters and between lobsters and their environment. There is an untapped opportunity for metagenomics, metatranscriptomics, and metabolomics to be added to the existing wealth of knowledge to more precisely track disease transmission, etiology, and host-microbe dynamics. Moreover, we need to gain this knowledge of wild lobster microbiomes before climate change alters environmental and host-microbial communities more than it likely already has, throwing a socioeconomically critical industry into disarray. As with so many animal species, the effects of climate change often manifest as changes in movement, and in this perspective piece, we consider the movement of the American lobster (Homarus americanus), Atlantic Ocean currents, and the microorganisms associated with either.