Genes involved in melanin production directly impact insect pigmentation and can affect diverse physiology and behaviours. The role these genes have on sex behaviour, however, is unclear. In the present study, the crucial melanin pigment gene black was functionally characterised in an urban pest, the German cockroach, Blattella germanica. RNAi knockdown of B. germanica black (Bgblack) had no effect on survival, but did result in black pigmentation of the thoraxes, abdomens, heads, wings, legs, antennae, and cerci due to cuticular accumulation of melanin. Sex-specific variation in the pigmentation pattern was apparent, with females exhibiting darker coloration on the abdomen and thorax than males. Bgblack knockdown also resulted in wing deformation and negatively impacted the contact sex pheromone-based courtship behaviour of males. This study provides evidence for black function in multiple aspects of B. germanica biology and opens new avenues of exploration for novel pest control strategies.

This article rediscovers the importance of food gifts in navigating the process of courtship in England during the long eighteenth century. Studies of courtship and gift-exchange to date have demonstrated how courting couples exchanged a wide range of gifts to produce and intensify feelings of love and advance their relationships toward the altar, from garters and gloves to ribbons, rings, portrait miniatures and locks of hair. Yet the edible gift has remained conspicuously absent from this picture. The article reinserts edible tokens into the historiography of love and marriage, revealing how they operated as an indispensable and unique part of the ‘gift mode’ during courtship. It demonstrates how courting couples exchanged a wide range of foodstuffs from cakes and sweetmeats to game, fowl, fish, exotic fruits and home-grown produce. In doing so, the article advances the burgeoning field of emotions and material culture by demonstrating how organic or perishable items could function as powerful emotional objects, able to nourish the human body, provide a source of sensual and gustatory pleasure and elicit feelings of joy, delight, love and desire. In turn, these gifts show courtship made everyday, transacted between couples and their families, and situated in gardens and squares, shops, theatres and around a family's tea table.

In this paper social relationships (as defined by Hinde) between age/sex classes of kangaroos, wallabies and rat-kangaroos are reviewed and characterized by frequencies, direction and, where possible, intensity of behavioural interactions, by their patterning in sequences and by distance regulation. Male social organization in the wild for larger non-solitary species is organized in an age/size-related hierarchy. Frequent interactions among equal-sized males stabilize this hierarchy and large males by their simple presence deter younger ones from courting.

Depending on social organization in the wild, the presence of one or more males, sometimes males from different age classes, is desirable from the animal welfare standpoint.

The structure of breeding groups can be greatly improved in terms of welfare and breeding optimization, when a diversity of social relationships are as close to natural conditions as possible.

Despite mutual taboos against exogamy, memoirs and similar materials written by Jews from Yemen contain a number of anecdotes describing love affairs and sexual encounters between Muslims and Jews prior to the mass migration of the vast majority of Yemen's Jews to Israel in 1949–50. These stories associate these liaisons with vulnerability, poverty, and marginalization. In them, sex and conversion to Islam are intrinsically connected, yet this interreligious intimacy leads not to resolution but to ongoing identity crises that persist beyond the community's realignment with a majority-Jewish society. The staging of the anecdotes in rural areas where shariʿa norms held only nominal sway, in watering places and hostels where strangers might interact, and at dusk, when identity is difficult to discern, heightened their ambiguity.

Basking sharks Cetorhinus maximus tend to aggregate in summer at favoured locations along Britain and Ireland's west coast. Sharks have been described approaching and close-following one another, often to one side. This has been interpreted as putative pre-mating behaviour. At aggregation sites around the Inner Hebrides we used boat-based observation and in-water and overhead drone video-photography to document behaviour and to determine the sex of individuals. It was confirmed that a shark will frequently move purposely towards another from a distance and swim to maintain a position either directly behind or closely to one side of a conspecific for short periods. Contrary to expectation, we found no relationship between the sex of a shark or its size and close-following. This suggests that following behaviours are not mainly related to courtship. Further, abrasions on the nose suspected to be related to male behaviour were found to occur on both sexes, although abrasions on pectoral fins, similarly suggestive of mating-related behaviour, were predominantly on females. Breaching by basking sharks has also been proposed as a means of attracting the opposite sex. We observed breaching by solitary sharks but commonly by sharks within aggregations, and at other times by more than one shark on the same day at the same time; but there was not any clear evidence to indicate that breaching is primarily related to mating. More likely individuals show close following chiefly for feeding-related hydrodynamic advantage. It remains plausible however that mature sharks make use of feeding aggregations to initiate pre-courtship behaviour.

In the Ecuadorian cloud forest, males of the parasitoid braconid wasp Napo townsendi Shaw displayed facultative lekking, appearing both singly and in groups of 2–7 on the leaf tops of various plant species. To attract females, they constantly employed a stereotypical, spread-winged calling behaviour, apparently releasing a sex pheromone combed from the lateral metasomal exocrine glands and applied to the wings and hind legs. Aggregated males used the same posture in conspecific agonistic displays, often leading to physical fighting. While female wasps were attracted to and mated with displaying singletons, they also made a choice among aggregated males. When females approached, males vibrated their wings in a brief courtship and mounted. Details of copulation behaviour, which lasted on an average of 3–4 min, are described. Without apparent physical weaponry, the displaying wasps successfully warded off attacks from an assortment of predatory arthropods, particularly salticid spiders. We present case studies of repeated unsuccessful predation attempts by salticids. Here, we postulate that calling and release of sex pheromone may double as both an intrasexual agonistic display and an aposematic advisory to predators that the wasps employ a chemical defence.

Studland Bay contains an extensive seagrass (Zostera marina) bed and two species of seahorse: spiny (Hippocampus guttulatus) and short snouted (H. hippocampus). All are protected under UK and international legislation. Five H. guttulatus have been tagged and all re-sighted several times within the seagrass bed. Home ranges of 30–400m2 were found. The three tagged males have all been observed to be pregnant throughout the summer months suggesting up to five broods per year. On one occasion the courtship display was recorded. This study has demonstrated the value of volunteer divers in monitoring which would not have been so successful without them. This project arose from concerns over negative impacts of boat anchoring and mooring on the seagrass habitat. It is hoped that the insights gained into site fidelity, territory size and breeding ecology of the seahorses will contribute to management plans for this unique site.

The age-specific mating incidence and mating behaviour of an aphidophagous ladybird beetle Coelophora saucia Mulsant were studied. Males started mating at the age of 4 days. Newly emerged females mated with older males albeit forcibly. The incidence of mating was 100% at the age of 10 days. Courtship involved five steps, viz. approach, watch, examine, mount and attempt, and was male dominated under laboratory conditions. Results indicate that physical cues probably play a role in the initiation of courtship, while chemical signals are probably involved in the continuation of courtship, culminating in intromission. The mating duration, latent period and number of bouts gradually decreased with increase in the number of matings; however, the interval between bouts slightly increased. Pseudo-mating with dead mates was observed in C. saucia. The oviposition period, fecundity and % egg viability were highest in females mated multiple times, while lowest in those that mated once.

During pair formation, cicadas produce acoustic signals that allow sexual partners to meet. The male is generally the emitter, producing calling songs at long range and courtship songs at short range, and the female generally the receiver. The male–female courtship behaviour of seven taxa belonging to the Palaearctic genus Tibicina is described here for the first time. Male courtship songs consisted of a succession of groups of pulses arranged in two sub-groups. They were short in duration with strong amplitude variations. In all taxa, courtship songs were preceded by a series of 1–5 audible wing-flicks. Differences in courtship song structure between two pairs of sympatric species, respectively T. corsica corsica/T. nigronervosa and T. corsica fairmairei/T. tomentosa, suggest that courtship signals could act as distinctive species mating recognition systems. In response to male acoustic signalling, females of T. c. corsica, T. c. fairmairei and T. nigronervosa produced audible wing-flicks such that both sexes established an acoustic duet ending in physical contact. In addition, males and females of T. tomentosa produced silent wing-flicks, a previously unknown behaviour, which could facilitate pheromone diffusion. Females did not exhibit a species-specific temporal pattern in acoustic reply to male courtship song and female wing-flick behaviour does not seem necessary for pair formation. Nevertheless, this strategy through male and female signalling ensured a reciprocal phonotactic approach that probably enhanced the likelihood for the two sexes to meet in complex habitats.

Alternative mating tactics are found in many species, and may have important implications for population genetics and speciation. The existence of such alternative mating tactics is well-documented in the three-spined stickleback Gasterosteus aculeatus, and sneaking and egg-stealing may occur in a significant proportion of matings under natural conditions. Sneaking can impose high costs on territorial males, both in terms of reduced reproductive output and caring for unrelated offspring. We ask whether territorial males adjust their behaviour in response to the risk of sneaking. In a field study of three-spined sticklebacks on the Isle of Arran, Scotland, territorial males were presented with glass bottles containing either a male, a female or neither, to address whether territorial males were more aggressive to other males in the presence of a female, and whether territorial males courted females less in the presence of another male. Behavioural observations showed that territorial males did not behave more aggressively towards rival males in the presence of a female, but did reduce their rate of courtship towards females in the presence of rival males. We conclude that territorial males adopt behavioural strategies that may reduce their risk of reproductive parasitism.

Adult body size and shape were examined in almost 1400 individuals of the tortoises Testudo graeca, T. hermanni and T. marginata from Greece. The size at maturity was greater in females than in males in all three species. Maximum and mean adult sizes were also greater in females than in males in T. graeca and T. hermanni. Males grew to a larger size than females in T. marginata, and mean adult size was similar in the sexes in this species. Sexual dimorphism of shape (adjusted for size covariate) was shown in most of the characters examined, and the degree of this dimorphism differed significantly among the three species. Differences were related to their contrasting courtship behaviours: horizontal head movements and severe biting in T. marginata, vertical head bobs and carapace butting in T. graeca, and mounting and tail thrusting in T. hermanni. There was no difference in the frequency of observations of courtship or fighting among the three species, but courtship was about 10 times more common than combat in males. All species showed greatest courtship activity in autumn; copulation was rarely observed in T. hermanni (only 0.36% of courting males) and not seen in the other species in the field. Observations made throughout the activity season indicated that feeding was equally common in males and females in all three species. Differences in shape were more likely to be the result of sexual selection than of natural selection for fecundity. Detailed predictions are made for sexual dimorphism of other characters in these species.

Plethodontid salamanders of the North American subfamily Desmognathinae offer excellent opportunities for an integrative understanding of the form, functions and phylogeny of sexual behaviour patterns. The first description of courtship in the Black Mountain dusky salamander Desmognathus welteri is presented. Once oriented toward their partners, males produce multiple tactile, visual and chemical stimuli that probably function to stimulate, or ‘persuade’, females to mate. Persuasion is accomplished by behaviour patterns that include head rubbing, butterfly, pulling and snapping, and perhaps nudging and tail undulation. Sperm transfer is indirect by a spermatophore that is deposited on the substrate during a sequence of behaviour patterns involving both sexes known as tail-straddling walk. Fine-scale synchronization and orientation of partners at this time is crucial for successful insemination. The evolutionary histories of eight sexual behaviour patterns for 19 taxa of desmognathine salamanders are then reconstructed. Our phyloethological analyses suggest that the courtship of desmognathines consists of a mosaic of ancestral (plesiomorphic) and derived (apomorphic) behavioural traits. The greatest variation among taxa involves behaviour patterns that are exhibited early in sexual encounters as, or shortly after, males orient toward females. Behaviour patterns that occur at closer range and most obviously are persuasive in function show less variation among taxa, and those that lead to sperm transfer (tail-straddling walk) are invariant. While our phyloethological analyses reveal aspects of the evolutionary history of behavioural form in the Desmognathinae, further work is needed before thorough analyses of behavioural functions can be conducted.

Frogs (Amphibia: Anura) have contributed greatly to our understanding of the functions and evolution of sexual behaviour patterns, but few studies have been conducted on ‘primitive’ taxa. Here we describe laboratory observations that characterize aspects of the courtship and mating of the tailed frog Ascaphus truei, one of the most basal of living frogs. Fertilization is internal (a rare and probably apomorphic state for anurans) and sperm transfer is via an erectile intrommitent organ, or ‘tail.’ This structure seems to be an autapomorphy. Inguinal amplexus accomplishes mating (probably a plesiomorphic state), but the combination of amplexus and copulation, previously termed copulexus, is unique (autapomorphic). Mate location is not mediated acoustically (sexual vocalizations probably are apomorphic), but may involve visual or chemical cues. In a competitive context, heavier males do not seem to enjoy an advantage in being the first to initiate mating, and rivals rarely displace males already engaged in copulexus by wrestling. The courtship and mating of the tailed frog consists of a mosaic of traits that are ancestral, derived and unique within the clade Anura. Efficient location and then (with internal fertilization) stimulation of females during copulexus may influence male reproductive success more than wrestling.