Factors influencing mate choice in Euschistus conspersus Uhler (Heteroptera: Pentatomidae)

Reproductive Patterns Drive the Gene Flow and Spatial Dispersal of Euschistus heros (Hemiptera: Pentatomidae)

Euschistus heros (Hemiptera: Pentatomidae) has two allopatric strains with a hybrid zone in central Brazil. Asymmetric dispersal and gene flow between these strains of E. heros have been observed, where the South strain (SS) moves more quickly to the northern regions of the country than the North strain (NS) to the southern areas. In addition, SS generally has a bigger body size and presents dark brown coloration, and NS is usually smaller in size and presents light brown coloration. Here, we studied the reproductive behavior and tested for the presence of assortative mating and reproductive barriers between the two allopatric strains of E. heros. Nonrandom mating was observed in the SS strain based on mating choice trials and the reproductive isolation indexes. SS females and males prefer to mate with their co-specific (same strain) partner, while NS insects showed no mating preference. The insect's pronotum width was positively associated with the mating choice suggesting size-assortative mating in E. heros. Reciprocal crosses between strains yielded similar reproductive outputs when compared with pure strain crosses, suggesting similar fitness of hybrid pure strains. The asymmetric gene flow in the hybridization zone that favors SS seems to be associated with the reproductive behavior of the species, which favors the typical phenotype found in the SS populations.

Environmental Correlates of Sexual Signaling in the Heteroptera: A Prospective Study

Sexual selection is a major evolutionary process, shaping organisms in terms of success in competition for access to mates and their gametes. The study of sexual selection has provided rich empirical and theoretical literature addressing the ecological and evolutionary causes and consequences of competition for gametes. However, there remains a bias towards individual, species-specific studies, whilst broader, cross-species comparisons looking for wider-ranging patterns in sexual selection remain uncommon. For instance, we are still some ways from understanding why particular kinds of traits tend to evolve under sexual selection, and under what circumstances. Here we consider sexual selection in the Heteroptera, a sub-order of the Hemiptera, or true bugs. The latter is the largest of the hemimetabolous insect orders, whilst the Heteroptera itself comprises some 40,000-plus described species. We focus on four key sexual signaling modes found in the Heteroptera: chemical signals, acoustic signaling via stridulation, vibrational (substrate) signaling, and finally tactile signaling (antennation). We compare how these modes vary across broad habitat types and provide a review of each type of signal. We ask how we might move towards a more predictive theory of sexual selection, that links mechanisms and targets of sexual selection to various ecologies.

Sexual experience has no effect on male mating or reproductive success in house mice

The ability to learn from experience can improve Darwinian fitness, but few studies have tested whether sexual experience enhances reproductive success. We conducted a study with wild-derived house mice (Mus musculus musculus) in which we manipulated male sexual experience and allowed females to choose between (1) a sexually experienced versus a virgin male, (2) two sexually experienced males, or (3) two virgin males (n = 60 females and 120 males). This design allowed us to test whether females are more likely to mate multiply when they encounter more virgin males, which are known to be infanticidal. We recorded females’ preference and mating behaviours, and conducted genetic paternity analyses to determine male reproductive success. We found no evidence that sexual experience influenced male mating or reproductive success, and no evidence that the number of virgin males influenced female multiple mating. Females always copulated with both males and 58% of the litters were multiple-sired. Females’ initial attraction to a male correlated with their social preferences, but neither of these preference behaviours predicted male reproductive success – raising caveats for using mating preferences as surrogates for mate choice. Male reproductive success was predicted by mating order, but unexpectedly, males that copulated first sired fewer offspring.

Lightweight males of Podisus nigrispinus (Heteroptera: Pentatomidae) neglect lightweight females due low reproductive fitness

Abstract Sexual choice by male stink bugs is important because females that experience food shortages lay fewer eggs with lower viability compared with well-fed females. In this study, we investigated whether Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) males fed with a low-quality diet during its nymphal stage show selectivity for sexual partners resulting in high-quality progeny. Lightweight males and females were obtained from nymphs fed weekly with Tenebrio molitor L. (Coleoptera: Tenebrionidae) pupae. By contrast, heavyweight males and females were fed three times a week and received an extra nutritional source: cotton leaves, Gossypium hirsutum L. (Malvaceae). Lightweight males preferred to mate with heavy females (77.78 ± 14.69%), whereas heavyweight males did not discriminated between light or heavyweight females. Females mated with lightweight males showed similar levels of reproduction to those mated with heavyweight males. The results provide an indication of the importance of male and female body weight for sexual selection in Asopinae stink bugs.

Evaluating aggregation membership and copulatory success in the stink bug, Euschistus conspersus, using field and laboratory experiments

The aggregation and mating behavior of the stink bug, Euschistus conspersus Uhler (Hemiptera: Pentatomidae) was investigated in a series of field and laboratory experiments. Marking of E. conspersus mating in aggregations in the field demonstrated that both sexes mate multiple times within aggregations on successive nights and with different partners, although ≈ 20% of the individuals of both sexes returned to aggregations but did not mate. Further analysis of mating patterns in caged aggregations revealed that heavy males and light females mated more frequently than their respective counterparts. Data are interpreted in terms of elucidating the function of benefits of multiple mating within aggregations for males and females.