Love bites: male frogs (Plectrohyla, Hylidae) use teeth scratching to deliver sodefrin precursor-like factors to females during amplexus

Background Efficient transfer of chemical signals is important for successful mating in many animal species. Multiple evolutionary lineages of animals evolved direct sex pheromone transmission during traumatic mating—the wounding of the partner with specialized devices—which helps to avoid signal loss to the environment. Although such direct transmission modes of so-called allohormone pheromones are well-documented in invertebrates, they are considered rare in vertebrates. Males of several species of the frog genus Plectrohyla (Hylidae, Anura) have elongated teeth and develop swollen lips during the breeding season. Here we investigated the possibility that these structures are used to scratch the females’ skin and apply allohormone pheromones during traumatic mating in several Plectrohyla species. Results Our behavioural observations revealed that males press their upper jaw onto the females’ dorsum during amplexus, leaving small skin scratches with their teeth. Histological examinations of the males’ lips identified specialized mucus glands, resembling known amphibian pheromone glands. Whole-transcriptome sequencing of these breeding glands showed high expression of sodefrin precursor-like factor (SPF) proteins, which are known to have a pheromone function in multiple amphibian species. Conclusions Our study suggests SPF delivery via traumatic mating in several anuran species: the males have specialized breeding glands in the lips for production and secretion and use their elongated teeth as wounding devices for application. We hypothesize that these SPF proteins end up in the females’ circulatory system, where understanding their exact function will require further molecular, physiological and behavioural testing.

Attraction of Choristoneura Rosaceana (Lepidoptera: Tortricidae) to Pheromone Blends in Ratios Produced in Females’ Pheromone Gland or Emitted by the Females in Michigan Apple Orchards

Trap captures of obliquebanded leafroller, Choristoneura rosaceana (Harris) to pheromone blends in ratios approximating those reported in pheromone glands and a novel blend based on a volatile headspace collection from live virgin females were evaluated in field experiments in Michigan apple orchards. In an initial field trapping study, pheromone lures composed of either a three- or four-component blend approximation of the blend present in female pheromone glands at doses ranging from 0.1 to 20 mg/lure were compared. The four-component blend was a combination of (Z)-11-tetradecenyl acetate (Z11-14:Ac), (E)-11-tetradecenyl acetate (E11-14:Ac), (Z)-11-tetradecen-1-ol (Z11-14:OH), and (Z)-11-tetradecenal (Z11-14:Al) in a ratio of 96.5:1.8:1.4:0.2, respectively, while the three-component blend lacked Z11-14:Al. Pheromone emissions by groups of virgin females and commercial lures were collected in the laboratory and analyzed by gas chromatography. These data were used to formulate a new pheromone lure that was compared to a commercial lure in a second trapping study. In the first field study, traps baited with 10 mg pheromones or above captured significantly more moths than traps baited with 1 mg or less, regardless of the blend. Surprisingly, groups of virgin females only emitted two detectable pheromone components, Z11-14:Ac and Z11-14:OH in a ratio of 37:63 which was substantially different from the blends detected in pheromone glands in the literature. The newly formulated pheromone lure based on females’ emission was more than twice as attractive as the commercial lure which emitted a 74:5:21 three-component blend of Z11-14:Ac, E11-14:Ac, and Z11-14:OH, indicating that the response of C. rosaceana to its pheromone was more strongly mediated by the pheromone quantity relative to the blend ratio.

The luring mantid: Protrusible pheromone glands in Stenophylla lobivertex (Mantodea: Acanthopidae)

The hitherto unknown pheromone gland of female Stenophylla lobivertex Lombardo, 2000, a poorly understood praying mantis distributed in the Neotropics, is described and figured. In contrast to other mantodeans, this species has a protrusible, bifurcated (Y-shaped) gland of 6 mm length. It is protracted by sexually receptive females during nighttime and only when undisturbed. The significance of this morphological and behavioral adaptation is discussed in light of the reproductive strategy of the species and its assumed rarity in the natural habitat.

Estimarea componenței feromonului sexual și determinarea ciclului de dezvoltare sezonieră a speciei Heiothis Armigera

The antennae reaction of the males Heliothis armigera was estimated by means of the electroantenographic apparatus to the components obtained from the extract of the pheromone glands of the females. It was found that the main component (Z11-16Al) caused a well-pronounced reaction on the male antennae. It has been shown that the pheromone emitted by the females of the native population does not differ from the pheromone emitted by the females of the species Heliothis armigera, which lives in the geographical area of the Asian continent. The seasonal sexual cycle of the species Heliothis armigera was determined in the conditions of the natural habitat of the Republic of Moldova.

Pheromone Producing Dorsal Abdominal Glands in Leptocoris augur

Morphology of the scent (pheromone) glands is the first and basic step in understanding the mechanism of working of this highly evolved and integrated system of communication in insects. Leptocoris augur contains a pair of large and distinct symmetric exocrine dorsal abdominal glands (DAGs) found in the dorsal abdominal segments. The glands are simple, voluminous, sac-like and bright orange that turn brown and downsized with age. They are invested with a large and dense network of trachea and open to the exterior via minute slit shaped openings in the form of ostioles that remain permanently open to the outside. The functional specificity of these glands can be associated with the activities ranging from aggregation to sexual behaviours like courtship and mating. The mating is not restricted to a specific season, being distributed all-round the year; however, the insect prefers low and humid temperature for mating and they can be seen congregating in huge numbers when the hot summers subside and the rainy season arrives. We didn’t observe any considerable variation in size of these glands with respect to the body size in between the instars and the adults. Further, there were no significant difference between males and females in terms of the size of these DAGs.

Sexual communication in day-flying Lepidoptera with special reference to castniids or ‘butterfly-moths’

Butterflies and moths are subject to different evolutionary pressures that affect several aspects of their behaviour and physiology, particularly sexual communication. Butterflies are day-flying insects (excluding hedylids) whose partner-finding strategy is mainly based on visual cues and female butterflies having apparently lost the typical sex pheromone glands. Moths, in contrast, are mostly night-flyers and use female-released long-range pheromones for partner-finding. However, some moth families are exclusively day-flyers, and therefore subject to evolutionary pressures similar to those endured by butterflies. Among them, the Castniidae, also called ‘butterfly-moths’ or ‘sun-moths’, behave like butterflies and, thus, castniid females appear to have also lost their pheromone glands, an unparallel attribute in the world of moths. In this paper, we review the sexual communication strategy in day-flying Lepidoptera, mainly butterflies (superfamily Papilionoidea), Zygaenidae and Castniidae moths, and compare their mating behaviour with that of moth families of nocturnal habits, paying particular attention to the recently discovered butterfly-like partner-finding strategy of castniids and the fascinating facts and debates that led to its discovery.