Drosophila females have an acoustic preference for symmetric males

Male attractiveness is subjective to exposure to males of different attractiveness in fruit flies

Mate choice is a crucial decision in any animal. In terms of fitness, the best mate is the one that leads to the most abundant and productive offspring. Pairing with a low-quality mate would reduce fitness, generating selection for accurate and subtle mate choice in all animal species. Hence, mate choice is expected to be highly context dependent, and should depend on other potential options. For instance, a medium-quality male can constitute the best option when all other males are in poorer condition, but not when there are better-quality males available. Therefore, animals are predicted to gather information about their social context and adapt their mate choice to it. Here, we report on experiments in which we manipulated the social environment of females of Drosophila melanogaster and found that after encountering a high or a low-quality male, they take more or less time to accept copulation with another male, suggesting that females adapt their mating strategy to their social context. We also report on a similar effect in D. biarmiceps. Thus, male attractiveness appears to depend on the quality of recently met males, suggesting that male attractiveness is subjective, indicating plastic and context dependent mate choice.

C. elegans males optimize mate-preference decisions via sex-specific responses to multimodal sensory cues

For sexually reproducing animals, selecting optimal mates is important for maximizing reproductive fitness. In the nematode C. elegans, populations reproduce largely by hermaphrodite self-fertilization, but the cross-fertilization of hermaphrodites by males also occurs. Males' ability to recognize hermaphrodites involves several sensory cues, but an integrated view of the ways males use these cues in their native context to assess characteristics of potential mates has been elusive. Here, we examine the mate-preference behavior of C. elegans males evoked by natively produced cues. We find that males use a combination of volatile sex pheromones (VSPs), ascaroside sex pheromones, surface-associated cues, and other signals to assess multiple features of potential mates. Specific aspects of mate preference are communicated by distinct signals: developmental stage and sex are signaled by ascaroside pheromones and surface cues, whereas the presence of a self-sperm-depleted hermaphrodite is likely signaled by VSPs. Furthermore, males prefer to interact with virgin over mated, and well-fed over food-deprived, hermaphrodites; these preferences are likely adaptive and are also mediated by ascarosides and other cues. Sex-typical mate-preference behavior depends on the sexual state of the nervous system, such that pan-neuronal genetic masculinization in hermaphrodites generates male-typical social behavior. We also identify an unexpected role for the sex-shared ASH sensory neurons in male attraction to ascaroside sex pheromones. Our findings lead to an integrated view in which the distinct physical properties of various mate-preference cues guide a flexible, stepwise behavioral program by which males assess multiple features of potential mates to optimize mate preference.

Organogenesis: Cell death matters in size and shape regulation

Anisotropic growth and large-scale morphogenetic movements contribute to the final size and shape of the adult Drosophila wing. A new study unravels an unexpected contribution of cell death, which follows a spatial and temporal pattern, to the growth of the wing and the acquisition of its elongated shape.

Cyto-Genotoxic and Behavioral Effects of Flubendiamide in Allium cepa Root Cells, Drosophila melanogaster and Molecular Docking Studies

Flubendiamide (FLB) is an insecticide that is commonly employed to control pests on a variety of vegetables and fruits, with low toxicity for non-target organisms. However, due to its widespread use, the environmental risks and food safety have become major concerns. In this study, the toxicity potential of FLB was studied in the model organisms, Allium cepa and Drosophila melanogaster. The cyto-genotoxic effects of FLB on the root growth, mitotic index (MI), chromosomal aberrations (CAs) and deoxyribonucleic acid (DNA) damage in A. cepa root meristematic cells were investigated using the root growth inhibition Allium test and Comet assays. FLB caused CAs in the form of disturbed ana-telophase, chromosome laggards, stickiness, anaphase-bridge and polyploidy depending on the concentration and the exposure time. The toxicity and genotoxicity of FLB at various doses (0.001, 0.01, 0.1 and 1 mM) on D. melanogaster were investigated from the point of view of larval weight and movement, pupal formation success, pupal position, emergence success and DNA damage, respectively. FLB exposure led to a significant reduction of the locomotor activity at the highest concentration. While DNA damage increased significantly in the FLB-treated onions depending on the concentration and time, DNA damage in the FLB-treated D. melanogaster significantly increased only at the highest dose compared to that which occurred in the control group. Moreover, to provide a mechanistic insight into the genotoxic and locomotion-disrupting effects of FLB, molecular docking simulations of this pesticide were performed against the DNA and diamondback moth (DBM) ryanodine receptor (RyR) Repeat34 domain. The docking studies revealed that FLB binds strongly to a DNA region that is rich in cytosine-guanine-adenine bases (C-G-A) in the minor groove, and it displayed a remarkable binding affinity against the DBM RyR Repeat34 domain.

Non-visual cues and indirect strategies that enable discrimination of asymmetric mates

The postulates of developmental instability-sexual selection hypothesis is intensely debated among evolutionary biologists, wherein despite a large amount of empirical data, evidence for or against it has been largely inconclusive. A key assumption of this hypothesis is that animals assess symmetry in potential mates as an indicator of genetic quality (developmental stability), and consequently use this information to discriminate against those with higher asymmetries while choosing mates. However, the perceptional basis that must underlie such discriminatory behavior (is symmetry a signal or is symmetry signaled) is not clearly defined. It is also argued that since asymmetry levels in natural populations are very low, the low signal-to-noise ratio would make accurate assessment of symmetry both difficult and costly. Rather than attempting to validate this hypothesis or even as to whether animals assess mate symmetry, this review simply aims to examine the plausibility that animals perceive symmetry (directly or indirectly) and consequently discriminate against asymmetric mates in response to perceived irregularities during courtship. For this, we review mate choice and courtship literature to identify potential sensory cues that might advertise asymmetry or lead to discrimination of asymmetric individuals. Although signaling associated with mate choice is commonly multimodal, previous studies on asymmetry have mainly focused on visual perception. In the light of a recent study (Vijendravarma et al., 2022, Proceedings of the National Academy of Sciences of the United States of America, 119, e2116136119), this review attempts to balance this bias by emphasizing on non-visual perception of asymmetry. In conclusion, we discuss the methodological challenges associated with testing the role of multimodal cues in detecting mate asymmetry, and highlight the importance of considering ecological, behavioral, and evolutionary aspects of animals while interpreting empirical data that test such hypothesis.