Costly traumatic insemination and a female counter-adaptation in bed bugs

Male bed bugs pierce females through the body wall and inseminate directly into the body cavity. It has previously been shown that such traumatic insemination carries costs for females, and sexual conflict regarding the mode of insemination should thus propel male-female coevolution. Since males accumulate sexually antagonistic adaptations, females should evolve counter-adaptations that efficiently abate the costs to females of sexual interactions. Yet, unambiguous experimental evidence for female counter-adaptations is lacking. In bed bugs, the spermalege (a highly modified region of the abdomen where the male usually pierces the female) may represent a female counter-adaptation. We assess the female costs of traumatic insemination by varying the rate of insemination on the one hand, and the rate and mode of piercing trauma to females on the other. Our results show that female mating costs are not extreme-elevated mating rate shortened female lifespan but had no significant effect on lifetime egg production. More importantly, additional abdominal piercing in the spermalege had no effect on females whereas even a very low rate of such piercing outside the spermalege reduced female lifetime egg production by 50%. Thus, females are well counter-adapted to the intrusive mode of insemination exhibited by male bed bugs and the costs of elevated mating are comparable with those in other insects, as predicted by theory. We therefore demonstrate that the spermalege efficiently reduces the direct costs of piercing trauma to females, and hence provide experimental evidence for a female counter-adaptation to a sexually antagonistic male trait.     

The spider Harpactea sadistica: co-evolution of traumatic insemination and complex female genital morphology in spiders

The males of invertebrates from a few phyla, including arthropods, have been reported to practise traumatic insemination (TI; i.e. injecting sperm by using the copulatory organ to penetrate the female''s body wall). As all previously reported arthropod examples have been insects, there is considerable interest in whether TI might have evolved independently in other arthropods. The research reported here demonstrates the first case of TI in the arthropod subphylum Chelicerata, in particular how the genital morphology and mating behaviour of Harpactea sadistica (Řezáč 2008), a spider from Israel, has become adapted specifically for reproduction based on TI. Males have needle-like intromittent organs and females have atrophied spermathecae. In other spiders, eggs are fertilized simultaneously with oviposition, but the eggs of H. sadistica are fertilized in the ovaries (internal fertilization) and develop as embryos before being laid. Sperm-storage organs of phylogenetically basal groups to H. sadistica provide males with last male sperm priority and allow removal of sperm by males that mate later, suggesting that TI might have evolved as an adaptive strategy to circumvent an unfavourable structure of the sperm-storage organs, allowing the first male to mate with paternity advantage. Understanding the functional significance of TI gives us insight into factors underlying the evolution of the genital and sperm-storage morphology in spiders.     

Sperm drinking by female catfishes: a novel mode of insemination

Synopsis We report on unique reproductive behaviour and a new mode of egg insemination in a small catfish Corydoras aeneus (Callichthyidae). A male courts a female by presenting his abdomen to her. Before releasing eggs, the female attaches her mouth to the male's genital opening and directly drinks his sperm. The sperm pass through her intestine and are discharged together with eggs into the pouch formed by her pelvic fins. Thus, eggs are mixed with fresh non-dispersed sperm in an enclosed space, ensuring effective insemination. This mode of insemination is novel to fishes, but is likely not restricted to catfishes of the genus Corydoras.     

Twin intromittent organs of Drosophila for traumatic insemination

In several animals, male genitalia create insemination wounds in areas outside the genital orifice of females. I report that such traumatic insemination (TI) occurs in the Drosophila bipectinata complex (Diptera: Drosophilidae) and illustrate a previously unknown evolutionary pathway for this behaviour. Flash fixation of mating pairs revealed the dual function of the paired claw-like basal processes, previously misidentified as a bifid aedeagus: (i) penetration of the female body wall near the genital orifice and (ii) sperm transfer into the genital tract through the wounds. Basal processes in closely related species (Drosophila ananassae and Drosophila pallidosa) also wounded females but did not transfer sperm; this represents a transitional state to TI as observed in the bipectinata complex. Copulatory wounding is suggested to occur in other allied species of the Drosophila melanogaster species group, including D. melanogaster. Ubiquitous sexual conflicts over mating may have led to the evolution of novel intromittent organs for insemination.     

Nonadaptive female pursuit of extrapair copulations can evolve through hitchhiking

Mounting evidence has indicated that engaging in extrapair copulations (EPCs) might be maladaptive or detrimental to females. It is unclear why such nonadaptive female behavior evolves. In this study, we test two hypotheses about the evolution of female EPC behavior using population genetic models. First, we find that both male preference for allocating extra effort to seek EPCs and female pursuit behavior without costs can be maintained and remain polymorphic in a population via frequency‐dependent selection. However, both behaviors cannot evolve when females with pursuit behavior suffer from a decline in male parental care. Second, we present another novel way in which female pursuit behavior can evolve; indirect selection can act on this behavior through a ratchet‐like mechanism involving oscillating linkage disequilibria between the target EPC pursuit locus and two other loci determining male mate choice and a female sexual signal. Although the overall positive force of such indirect selection is relatively weak, our results suggest that it may still play a role in promoting the evolution of female EPC behavior when this behavior is nonadaptive (i.e., it is neutral) or only somewhat maladaptive (e.g., males only occasionally lower parental care when their mates pursue EPCs).     

Refutation of traumatic insemination in the Drosophila bipectinata species complex

Traumatic insemination (TI) is a rare reproductive behaviour characterized by the transfer of sperm to the female via puncture wounds inflicted across her body wall. Here, we challenge the claim made by Kamimura (Kamimura 2007 Biol. Lett. 3, 401–404. (doi:10.1098/rsbl.2007.0192)) that males of species of the Drosophila bipectinata complex use a pair of claw-like processes (claws) to traumatically inseminate females: the claws are purported to puncture the female body wall and genital tract, and to inject sperm through the wounds into the lumen of her genital tract, bypassing the vaginal opening. This supposed case of TI is widely cited and featured in prominent subject reviews. We examined high-resolution scanning electron micrographs of the claws and failed to discover any obvious ‘groove’ for sperm transport. We demonstrated that sperm occurred in the female reproductive tract as a single-integrated unit, inconsistent with the claim that sperm are injected via paired processes. Laser ablation of the sharp terminal ends of the claws failed to inhibit insemination. We showed that the aedeagus in the complex delivers sperm through the vaginal opening, as in other Drosophila. The results refute the claim of TI in the Drosophila bipectinata species complex.     

Sex determination: ways to evolve a hermaphrodite

Most species of the nematode genus Caenorhabditis reproduce through males and females; C. elegans and C. briggsae, however, produce self-fertile hermaphrodites instead of females. These transitions to hermaphroditism evolved convergently through distinct modifications of germline sex determination mechanisms.     

A unique teleost dermal organ in a new European genus of fishes (Teleostei: Gobioidei)

The freshwater fish fauna of Greece is a diverse assemblage of mediterranean, Ponto-Caspian, and endemic western Greek elements. In the last category, a gobiid from Epirus has been found to possess a dermal perianal organ unique among teleosts, as well as systematic features warranting recognition of a new genus, Economidichthys gen. nov. ( type-species Gobius pygmaeus Holly, 1929). The perianal organ is a sharply-demarcated, pitted area on the rear abdomen. Light-and electron-microscopy has revealed numerous specialized microvillous cells lining the pits and evidently secretory in function. Presence of the organ in both sexes, its ventral position and the secretory activity originally suggested an attachment role rather than involvement in reproduction, but obvious correlation with habitat is lacking and alternative functions are discussed.     

Reducing cooling load and lifecycle cost for residential buildings: a case of Lahore,Pakistan

Purpose

Buildings consume a large amount of energy for space cooling during the summer season, creating an overall sustainability concern. The upfront cost associated with sustainability repels the decision-makers to often end up adopting solutions that have huge operations and maintenance costs. Therefore, the purpose of this study is to assess the lifecycle cost (LCC) implications of optimum configurations of active and passive strategies for reducing the cooling load in buildings.

Methods

Several green building active and passive strategies and technologies were assimilated and their thermal performance in a hot semi-arid climate of Lahore in Pakistan using DesignBuilder V6.1 was simulated to obtain the most optimum cooling load configuration. Furthermore, LCC is estimated, and overall efficiency is evaluated to identify the most effective space cooling configuration.

Results and discussion

The results suggest that a configuration of EPS for external wall insulation, vertical louvers for external shading, 6 mm blue HRG (low-E soft coated)?+?12 mm air space?+?6 mm clear glass for windows, polystyrene as roof insulation, cross ventilation through windows, and LED lighting system has the best performance. This is the first-of-its-kind study in the hot semi-arid climate of South Asia with the city of Lahore in Pakistan as the test case and can be generalized for places with similar conditions. The findings will help the decision-makers in selecting the most load-efficient and cost-effective green building technologies to help improve overall sustainability.

Conclusion

The implementation of the proposed strategies not only aids in providing user-friendly and effective decision-making but also promotes the adoption of sustainability in buildings by leveraging the existing green building technologies to enhance the environmental and economic aspects. This is a promising approach to facilitate the spread of green building construction in developing countries. It is recommended to utilize the strategies grouped in Scenario 8 to achieve a reduced cooling load and LCC of a residential building throughout its lifecycle.

     

Comparison of artificial insemination and natural service cost effectiveness in dairy cattle

Reproductive efficiency in the dairy herd is the most important factor for its economic success and a major concern for dairy farmers when using artificial insemination (AI) or natural service (NS). Our objectives were to estimate, compare and analyse the costs associated with breeding cattle by do-it-yourself (DIY) AI and NS and identify the factors that influence them, under typical dairy farming conditions in Greece. A simulation study was designed based on data from 120 dairy cattle farms that differed in size (range 40 to 285 cows) and milk production level (4000 to 9300 kg per cow per year). Different scenarios were employed to estimate costs associated directly with AI and NS as well as potentially extended calving intervals (ECI) due to AI. Results showed that bull maintenance costs for NS were €1440 to €1670 per year ($1,820 to $2,111). Direct AI costs were higher than those for NS for farms with more than 30 cows and ECI constituted a considerable additional burden. In fact, amongst the factors that affected the amount of milk needed to cover total extra AI costs, number of days open was the dominant one. Semen, feed and heifer prices had a very small effect. When, hypothetically, use of NS bulls results in a calving interval of 12 months, AI daughters with a calving interval of 13.5 months have to produce about 705 kg of additional milk in order to cover the extra cost. Their actual milk production, however, exceeds this limit by more than 25%. When real calving intervals are considered (13.0 v. 13.7 months for NS and AI, respectively) AI daughters turn out to produce more than twice the additional amount of milk needed. It was concluded that even under less than average management conditions, AI is more profitable than the best NS scenario. The efficient communication of this message should be a primary concern of the AI industry.     

Body-size evolution: how to evolve a mammoth moth.

Separate recent studies have revealed the physiological changes underlying the evolution of body size in an insect and advanced our understanding of the genetics of insect growth. These studies highlight the gulf between physiological and genetic studies of growth control and the exciting opportunities for unification of these fields.     

A pharmacological and endocrinological study of female insemination inPhormia regina (Diptera: Calliphoridae)

Injections of octopamine, dopamine, and the octopaminergic agonists, clonidine and naphazoline, into the thoracic hemocoel enhanced female insemination in sugar-fed (sexually unreceptive)Phormia regina. Topical applications of the juvenile hormone (JH) analogue, methoprene, also enhanced female insemination in sugar-fed (sexually unreceptive)P. regina. Since JH plays a role in receptivity in protein-fed females, it was originally hypothesized that one agonist, clonidine, enhanced female insemination by acting on the corpus allatum (CA) to increase JH biosynthesis. Two or three doses of the antiallatal agent, precocene II, prior to administration of clonidine, did not inhibit clonidine-enhanced female insemination. Removal of the corpus allatum also did not have a significant effect on clonidine-enhanced female insemination. Measurement of juvenile hormone (JH) biosynthesis/release in corpora allata, which were removed at 1, 3, 5, and 7 h postinjection, revealed that clonidine does not affect JH biosynthesis/release. Our study reveals a possible role for the biogenic amines in female insemination in insects. We suggest that the octopaminergic agonist, clonidine, acts downstream from the corpus allatum on the regulatory mechanisms involved in female insemination.     

Evolution of female colours in birds: The role of female cost of reproduction and paternal care

Female ornamentation is frequently observed in animal species and is sometimes found as more evolutionary labile than male ornamentation. A complex array of factors may explain its presence and variation. Here we assessed the role of female cost of reproduction and paternal care. Both factors have been pinpointed as important by theoretical studies but have not been investigated yet in details at the interspecific level. We worked on 133 species of North temperate Passeriformes bird species for which both the clutch volume – here taken as the proxy of female cost of reproduction – and amount of paternal care are relatively well known. Using spectrometry, we measured the whole-body coloured plumage patches and quantified three metrics corresponding to brightness (i.e. achromatic component), colour chromaticity (i.e. intensity) and colour volume (i.e. diversity). We found a strong association between male and female colour metrics. Controlling for this association, we found additional small but detectable effects of both cost of reproduction and paternal care. First, females of species with more paternal care were slightly brighter. Second, the interaction between the level of paternal care and egg volume was correlated with female colour intensity: females with more paternal care were more chromatic, with this association mostly present when their investment in reproduction was low. Together these results suggest that female cost of reproduction and paternal care are part of the multiple factors explaining variation of female coloration, besides the strong covariation between male and female coloration.     

Production of a hybrid between the bedbugs Cimex hemipterus and Cimex lectularius

Of 479 eggs laid by female Cimex lectularius Linnaeus and C.hemipterus (Fabricius) mated by males of the other species, one was fertile and gave rise to a first stage nymph. The egg showed sculpturing typical of C.hemipterus, the female parent, and the nymph conformed to the narrow pronotum and abdomen of this species, being significantly different from C.lectularius in the width of the abdomen. Because the orientation and lengths of the bristles on the sides of the abdomen were distinctly different from C.hemipterus and closely resembled C.lectularius, the single nymph obtained from the cross C.hemipterus x lectularius was interpreted as being a hybrid rather than a product of parthenogenesis.     

Reducing crop losses by gene-editing control of organ developmental physiology

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