A larval aggregation pheromone as foraging cue for insectivorous birds

Although birds have traditionally been considered anosmic, increasing evidence indicates that olfaction plays an important role in the foraging behaviours of insectivorous birds. Recent studies have shown that birds can exploit herbivore-induced plant volatiles and sexual pheromones of adult insects to locate their prey. Many insectivorous birds prey on immature insects, providing relevant ecosystem services as pest regulators in natural and agricultural ecosystems. We asked whether birds could rely on chemical cues emitted by the immature stages of insects to prey on them. To address this question, we performed field experiments to evaluate if insectivorous birds can detect the aggregation pheromone produced by the larvae of the carpenter worm, Chilecomadia valdiviana . Groups of five artificial larvae were placed in branches of 72 adult trees in a remnant fragment of a sclerophyllous forest in central Chile. Each grouping of larvae contained a rubber septum loaded with either larval pheromone as treatment or solvent alone as control. We found that the number of larvae damaged by bird pecks was significantly higher in groups with dispensers containing the larval extract than in control groups. Our results show that birds can rely on immature insect-derived chemical cues used for larvae aggregation to prey on them.

A Fatty Acid Anabolic Pathway in Specialized-Cells Remotely Controls Oocyte Activation in Drosophila

ABSTRACTPheromone-mediated partner recognition is crucial for maintenance of animal species. Here, we discover a metabolic link between pheromone and gamete physiology. In female genital tract, oocyte maturation is arrested at a specific meiotic-phase. Release of this arrest, called oocyte-activation, is triggered by a species-dependent signal. We show in Drosophila melanogaster that oenocytes, which produce the fatty acids (FAs) used as precursors of cuticular hydrocarbons (CHCs), including pheromones, are also essential for oocyte activation. We identified a set of FA-anabolic enzymes required within oenocytes for the synthesis of a particular FA that is not a CHC precursor but controls oocyte activation. Our study thus reveals that two tightly linked FA-anabolic pathways act in parallel, one to produce sexual pheromones, the other to initiate embryonic development. Given that pheromone-deficient Drosophila melanogaster females are highly attractive for males irrespective of their species, this oenocyte function might have evolved to prevent hybrid development.

Metode de monitorizare și combatere a dăunătorului molia minieră a tomatelor ( Tuta absoluta) în spațiile protejate

Tuta absoluta comes from South America. In Europe it was reported for the first time in Spain in 2006. In Republic of Moldova, according to the literary sources, the tomato moth was reported for the first time in 2013 (in Chișinău). In the absence of some efficient prevention and combating measures of the Tuta absoluta pest it spread more and more, and became a pest of major concern for all the Moldavians farmers which deals with the cultivation of tomato crops in the protected areas. Following the phyto sanitary controls the most cases was found the central region of the country. For the monitoring of the tomato moth pest, in the protected area, was used the water universal trap, the ultraviolet light, the colored adhesive plates and sexual pheromones. As a chemical method of the tomato moth pest combating was used: the insecticide Afirm WG dose of 1. 50 kg/ha.

Gland composition in sexually dimorphic skin structures of two species of Hylid frogs: Plectrohyla guatemalensis and Ptychohyla hypomykter

Secondary sexual characters form a diverse group of traits widely spread in amphibians. Within anurans, the Hylini tribe represents an interesting group to examine the evolution of this type of characters because it has different skin structure modifications, including ventrolateral glands, nuptial pads, and unique swollen upper lips. We analysed the skin gland composition in the upper lip of Plectrohyla guatemalensis and the ventrolateral gland of Ptychohyla hypomykter (Hylidae: Hylinae: Hylini). Each of these species is characterized by a different type of sexually dimorphic skin gland; specialized mucous glands (SMGs) in Pl. guatemalensis and specialized serous glands (SSGs) in Pt. hypomykter. The SMGs conform to the general type of sexually dimorphic skin glands in amphibians, whereas SSGs are very rare. Because SMGs are likely involved in the production of sexual pheromones, their distinctive location and their co-occurrence with other secondary sexual characters like long and pointed maxillary and premaxillary teeth in Pl. guatemalensis suggests that the system used for their delivery may be a distinguishing behavioral feature in this species. The presence of both types of glands in Pt. hypomykter (SMGs in nuptial pads, and SSGs in ventrolateral glands) suggests a different or, at least, a complementary role of these two types of glands during reproduction.

Aspects of mating behavior and antennal sensilla in Anomala inconstans Burmeister, 1844 (Coleoptera: Scarabaeidae: Rutelinae)

When suitable, adults of Scarabaeidae usually form swarms to find food and breeding sites. The steps of mating behavior can be mediated by chemical communication, and antennal sensilla are released volatiles detection structures, as sexual pheromones. In present work the mating behavior and the antennal sensilla of Anomala inconstans Burmeister, 1844 are described. The study was conducted at the Universidade Estadual de Mato Grosso do Sul, Cassilândia, Brazil from March 2015 to December 2017. Adults were collected through a light trap and taken to the laboratory for studies. Field and laboratory observations provided data for the description of the steps of mating behavior. Adults swarms were registered from September to November 2015 at 05:30 pm to 00:00 am. Females display a calling behavior from 05:25 pm to 08:00 pm, in which they rub their posterior legs against their abdomen, and after a few minutes males are able to locate them. In laboratory, the mating process lasted 20.4 minutes on average, and the possibility of chemical communication between adults was here discussed. The antennae of the species have trichoid, chaetica, placoid types I, II and III, and coeloconic types I and II sensilla. Placoid sensilla are the most abundant and females have more sensilla than males.

Extract of olive fruit fly males (Diptera: Tephritidae) attract virgin females

Research conducted during the past three decades suggests that in contrast to most other tephritid fruit flies, in which sexual pheromones are produced by males, the olive fruit fly Bactrocera oleae (Rossi) relies for its sexual communication on a pheromone that is produced by females. However, our present study suggests that virgin, mature females are attracted to male odors. In olfactometer assays extracts of male bodies obtained with a two-solvent system of methanol and dichloromethane were highly attractive to virgin females. This was observed during the last two hours of the photophase, when males are sexually active, but not during the first hours of the photophase, or when mated females were tested. Extracts of male bodies obtained with diethyl ether were also attractive to virgin females, albeit not as strongly as the two-solvent extracts. These results strongly indicate that males of the olive fruit fly elicit attraction to virgin females based on olfactory stimuli. The importance of these findings for understanding the sexual behavior of the olive fruit fly is discussed.

Target and Non‑Target Moth Species Captured by Pheromone Traps for Some Fruit Tortricid Moths (Lepidoptera)

Efficiency of the synthetic sexual pheromones for five tortricid species, viz. Grapholita funebrana Treitschke, 1835, G. janthinana (Duponchel, 1835), G. lobarzewskii (Nowicki, 1860), G. molesta (Busck, 1916), and Pandemis heparana (Denis & Schiffermüller, 1775), was evaluated in two areas in the SE part of the Czech Republic. The lures for G. funebrana produced by the Pherobank showed a higher selectivity and efficiency than those by the Propher. On the contrary, pheromones for G. molesta by the Propher are more effective than those by the Pherobank. Besides the target species, 29 non-target tortricid species and 25 other Lepidoptera species were captured. The number of non-target tortricid species was comparable by the attractants for all species (15 – 17 spp.), except Pandemis heparana (only 7 spp.). The most abundant non-target Tortricidae were Cnephasia stephensiana (Doubleday, 1849), Hedya pruniana (Hübner, 1799), and Epiblema cirsiana (Zeller, 1843). Cacoecimorpha pronubana (Hübner, 1799) was recorded in outdoor conditions of the Czech Republic for the first time. Celypha rosaceana (Schläger, 1847) was found as new for Moravia. Oegoconia novimundi (Busck, 1915) (Autostichidae) was attracted by the lures for Grapholita funebrana and G. molesta in unusually high number of specimens.

Sexy Mouth Odour? Male Oral Gland Pheromone in the Grain Beetle ParasitoidLariophagus distinguendus(Förster) (Hymenoptera: Pteromalidae)

Throughout the animal kingdom, sexual pheromones are used for the attraction of mates and as courtship signals but also enable sexual isolation between species. In the parasitic waspLariophagus distinguendus, male courtship behaviour consisting of wing fanning, antennal stroking of the female antenna, and head nodding stimulates female receptivity leading to copulation. RecentlyL. distinguenduswas reported to consist of two different lineages, which are sexually isolated because males fail to elicit receptivity in foreign females. It is unclear, however, which part of the courtship behaviour triggers female receptivity and therefore could be a mechanism causing sexual isolation. Here we show that inL. distinguendusa nonvolatile male oral pheromone is essential to release the female receptivity signal. In contrast, male wing fanning and antennal contact play a minor role. Additionally, the composition of the oral pheromone depends on the developmental host and females learn the composition upon emergence from the host substrate. These results will enable more detailed work on oral sexual pheromones to answer the question of how they are involved in the speciation process ofL. distinguendusand other parasitoid species, for a better understanding of the huge biodiversity in this group.