Effects of testosterone in the VMN on copulation,partner preference,and vocalizations in male rats

The present study tested whether testosterone propionate (TP) implanted in the ventromedial nucleus (VMN) of the hypothalamus could initiate performance, motivational, or sociosexual components of sexual behavior in castrated male rats. Twenty-seven intact male Long Evans rats were pretested for copulation, partner preference, and 50-kHz vocalization and were subsequently castrated. Approximately 3 weeks after castration, males were retested to confirm that these behaviors had declined, and groups were assigned. Groups 1 and 2 were implanted with bilateral stainless steel cannulae directed at the VMN that were either filled with TP (TVMN group) or remained empty (Blank group). A third group (TSC) was implanted subcutaneously with two 10-mm Silastic capsules filled with testosterone. Restoration of behavior was measured for 2 weeks after implants. We found that copulation and 50-kHz vocalization were not restored by TP in the VMN alone. However, partner preference returned to preoperative levels in both the TVMN and TSC groups, indicating that TP in the VMN was sufficient to restore sexual motivation. Following behavioral testing, prostate glands and seminal vesicles were weighed and confirmed that TP did not leak into the periphery in the TVMN group. Immunostaining for androgen receptors also verified that TP spread was confined to the immediate area surrounding the cannula tip. These results suggest that androgen activation at the VMN is sufficient to induce the motivational components of male sexual behavior, whereas activation of other brain sites is required for copulation and ultrasonic vocalization.     

Leg tegumental glands and male rubbing behavior at leks inPolistes Dominulus (Hymenoptera: Vespidae)

In summer, males of Polistes dominulus defend adjacent territories at landmarks. Patrol flights are interrupted by stops at selected perches and conspicuous dragging movements of the last sternites and all the legs over the substrate, especially at a high intruder density. Leg rubbing is regularly associated with prolonged grooming sessions. Single secretory cells, resembling the sternal glands formerly described in this species (class 3 ducted glands), were found in all the legs (in the femur, the tibia, and especially the tarsus) and in both sexes. Leg tegumental gland cells, like sternal glands, are probably a source of pheromones. They have not previously been described in polistine wasps.     

Ecdysone and a dietary alkaloid interact in the development of the pheromone gland of a male moth (Creatonotos,Lepidoptera: Arctiidae)

Summary Hair-covered scent organs of the male arctiid moth Creatonotos produce and dissipate the volatile pheromone hydroxydanaidal. The biosynthesis of this substance depends quantitatively upon the uptake of pyrrolizidine alkaloids (PA) with the larval foodplant. The size of the tubular, eversible scent organ (corema) is also positively correlated with the ingested amount of the same alkaloid, which acts like a specific growth factor. After an assessment of the corema normogenesis by Rick-Wagner (PhD thesis, University of Cologne, 1986) we injected PA into PA-free raised larvae, prepupae, and pupae. We found that the PA competence (sensitivity) of the corema anläge terminates with the first prepupal day. Ecdysone titer determinations (radioimmunoassay) are in agreement with those in other moth species. Ligated (ecdysone-free) pupal abdomina never developed imaginal structures, with or without earlier PA application. Ecdysone injection into ligated pupal abdomina of PA-fed specimens initiated the development of imaginal structures and also of coremata of more than (ecdysone-free) control size. Pupal abdomina without PA pre-treatment only developed very small coremata. With these experiments we have separated and identified two morphogenetic control agents of corema development: the dietary PA specifies the size of the organ whereas ecdysone induces the anlage to proliferate within these PA-dependent ranges and to differentiate adult structures, as it does with other imaginal anlagen.     

The evolution of food-producing glands in eusocial bees (Apoidea,Hymenoptera)1

A food-producing role for cephalic exocrine glands has arisen independently in both taxa of highly eusocial bees, Apis and Meliponini. With several exceptions, there is little evidence that food is produced by glands of solitary bees or by most bees at lower levels of sociality. We suggest that this association with sociality is due to four adaptive features of these glands: (1) food from the glands allows feces from queens and larvae to have a small volume, (2) the queen's fecundity can be increased, (3) nutrient recovery via cannibalism can be facilitated, and (4) rearing of emergency replacement queens is accelerated. Acceleration of the rearing of other castes and of queens in the normal process of colony fission is not clearly an advantage ascribed to these glands. Trophic eggs produced by meliponine colony workers are analogous to the secretions from food-producing glands in Meliponini and Apis workers.     

Morphology of male reproductive system in three species of Trypoxylon (Trypargilum) Richards (Hymenoptera: Crabronidae)

Variations in the adult male reproductive system among different groups of Hymenoptera offer characteristics that help studies on behavior and phylogenetics. The objective of this study was to describe the adult male reproductive system of three Trypoxylon (Trypargilum) species. For that, tissues were disseced, fixed in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and postfixed in 1% osmium tetroxide. The material was dehydratated and embedded for light and electron transmission microscopes. The species have similar reproductive systems, which are formed by a pair of testes, each one with three fusiforme follicles, from which emerges an efferent duct that later joins forming a deferent duct. The deferent duct opens into an ejaculatory duct. The first half of the deferent duct is enlarged and differentiated in a region specialized in sperm storage, the seminal vesicle. The accessory gland flows in the post-vesicular region of the deferent duct. The testes and vesicles are both covered with a conjunctive capsule. Sexually mature individuals have all spermatogenesis stages in their follicles. Sperms are released from testes in bundles which are disorganized inside seminal vesicles.     

Neotropical harvestmen (Arachnida,Opiliones) use sexually dimorphic glands to spread chemicals in the environment

Sexually dimorphic glands have convergently appeared in animals and are often responsible for the production of pheromones. In the suborder Laniatores of the order Opiliones (Arachnida), glands of such type are widespread, but there is not a single paper on how they are used. Using Scanning Electron Microscopy and a behavioral approach, we describe glandular openings and how these glands are used, in the harvestmen Gryne perlata and Gryne coccinelloides (Cosmetidae). Males of these two species have glandular openings on the metatarsi of legs I and on the metatarsi IV. Males were shown rubbing the glands of the metatarsi I against their other legs, whereas glands on the metatarsi IV are gently touched on the substrate or rubbed either against other legs, or against the substrate. Not all behaviors were seen in both species.     

A new species of Quexua from southeastern Peru (Hymenoptera, Crabronidae)

A distinctive new species of the crabronine wasp genus Quexua Pate is described and figured from a single male collected from lowland Amazonian rain forest in southeastern Peru. Quexua cicrasp. n. is the only species in the genus known with a sessile metasoma.     

Histological examinations of facial glands in <Emphasis Type="Italic">Saccopteryx</Emphasis><Emphasis Type="Italic">bilineata</Emphasis> (Chiroptera,Emballonuridae), and their potential use in territorial marking

Scent marking is widespread among individuals of Mammalia species, especially in resource defence social systems. Apart from urine and faeces that are used for claiming resource ownership, specialised scent glands are the main source of secretions in scent marking individuals. Most previous studies have described secretory epithelia macroscopically, since many glands are conspicuous. But macroscopically inconspicuous scent glands or morphological structures might then be overlooked. In Saccopteryx bilineata (greater sac-winged bat), behavioural observations suggest that both sexes have, apart from the conspicuous gular glands of males, specialised facial glands to display territorial marking. We investigated the facial glands of two males and one female S. bilineata histologically and found, first, that both sexes possess a bilateral symmetrically intermandibular gland, which is composed of a bed of modified apocrine sudoriferous cells. Second, we found lip glands consisting of modified apocrine sudoriferous cell units with pigmented ducts around the upper and the lower lip. Both gland types are probably involved during territorial marking.     

Ultrastructure of male accessory glands of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae)

The ultrastructure of the male accessory glands of the blow fly, Chrysomya megacephala (Fabricius), was presented using light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A pair of accessory glands was separated at opposite sites. Morphometric results using LM yield evidenced no significant difference in the median of either length or width of the left and right glands. A significant increment in both length and width was seen to plateau between three to six days. SEM observation showed that the surface of the glands revealed a faint irregular groove pattern throughout, and it was occasionally penetrated by tracheoles. Each gland was a slender, elongated sac‐like tubule having apical rounded ends, with a slight constriction at the sub‐apical part of the gland being observed occasionally. TEM analyses of three‐day‐old males showed that the glands consisted of external capsular cells with a basement membrane underneath, glandular cells, and gland lumen. The capsular cell was flat and contained a nucleus with electron dense material in the nuclear envelope. The glandular cell, appearing as columnar, consisted of a vacuolated component that contained a large oval nucleus centrally or sub‐basally located, with dense mitochondria, numerous rough endoplasmic reticulum, and secretory vesicles containing electron‐lucent materials. In the gland lumen, the cross‐section through the middle portion revealed dense secretory materials, characterized by electron‐dense materials. Some sections revealed a large lumen where secretion accumulates within the delicate sac. The seven‐day‐old glands exhibited a remarkable change in the lumen, where the whole space contained a large amount of secretory materials, with the electron‐dense materials being characterized as similar to those observed in three‐day‐old glands. About four prominent types of secretions were observed on the basis of difference in electron‐density.     

Diversity and function of male antennal glands in Cynipoidea (Hymenoptera)

The functional anatomy of antennal glands located either on the 3rd or on the 3rd and 4th antennomeres in males of several species of cynipoids was investigated. SEM observations revealed variously modified antennomeres with elevated plates, tyloids and excavated areas. In all the cases, the antennomeres are equipped with cuticular pores, corresponding internally to cuticular ducts. TEM studies showed the presence of type III integumentary glands, as classified by Noirot & Quennedey. Each glandular unit is made up of an innermost secretory cell, producing the secretion, and an outermost canal cell, producing the evacuating duct. The secretion passes through the duct and reaches the cuticular pores, concentrated in a ventro-lateral portion of the antennomere called the 'release and spread structure'. Both in Cynipidae and in Eucoilinae (Figitidae), the courtship behaviour includes a pre-copulatory phase characterized by intense antennal stroking. Bioassays in the eucoilins Leptopilina boulardi and L. heterotoma showed that these glands are the production site of a contact sex recognition pheromone, necessary for the female to accept the male.     

Faecal DNA typing as a tool for investigating territorial behaviour of badgers (Meles meles)

We use data from three social groups of badgers (Meles meles) to illustrate how faecal DNA genotyping could be used in scent-marking studies. Faecal samples collected from latrines were genotyped to determine the individual identity and sex of badgers engaging in territorial behaviour and the frequency with which those individuals defecated at particular latrines. The method is potentially applicable to other species of carnivores that use latrines to mark their territories.     

Comparing the relative amount of testosterone required to restore sexual arousal, motivation, and performance in male rats

It is well established that male rat reproductive behaviors including sexual arousal, motivation, and performance are dependent on circulating levels of testosterone (T). The present study was designed to (1) compare the relative amount of T required to restore these different aspects of behavior in castrated rats, and (2) create an animal model for clinical populations with sexual impairments. Twenty-nine male Long–Evans rats were tested before and after castration for sexual performance (copulation), motivation (partner preference), and arousal (50 kHz ultrasonic vocalizations; measured together with scent marking). Sexual arousal was also inferred from copulation data. Rats were then assigned to one of four groups, and T was re-introduced via Silastic capsule implants varying in length and content: No T (empty capsules), Low T (2 mm capsules), Medium T (5 mm capsules), or High T (two 10 mm capsules). The highest dose was intended to restore physiological levels. Results indicate that High T is required for 50 kHz vocalizations, while Medium T was sufficient for the restoration of copulation, partner preference, and scent marking. These data suggest that sexual arousal may be most sensitive to reductions in testosterone. The role of T levels in measures of generalized and specific (sexual) arousal is discussed in the context of other reproductive behaviors. Furthermore, because the Low T group showed impairments across all behaviors during post-implant tests, we propose that these animals may provide a good animal model for studying clinical conditions marked by reduced motivation and arousal, including Hypoactive Sexual Desire Disorder.     

Geographic variation in the carotenoid plumage pigmentation of male house finches (Carpodacus mexicanus)

Geographic variation in both the colour and pattern of carotenoid plumage pigmentation displayed by males in two subspecies of house finches ( Carpodacus mexicanus frontalis and C. m. griscom ) was quantified. The extent of ventral carotenoid pigmentation (patch size) differed markedly between these two subspecies; frontalis males from the U.S. (New York, Michigan, California and Hawaii) displayed a medium patch extending from their throats to their lower bellies, while griscomi males sampled in Guerrero, Mexico displayed small patches restricted to their throats. Frontalis males sampled in Michigan and New York and griscomi males were relatively bright in colouration, while frontalis males sampled in Hawaii were relatively drab. Populations of frontalis in California showed substantial local variation in average male colouration: in two areas only 12 km apart males were as colourful and as drab as any population sampled. In aviary experiments in which they were fed either a plain seed diet or a diet supplemented with red carotenoid pigments during moult, males from all populations converged on a similar appearance, except that griscomi males attained a brighter plumage than frontalis males when their diet was supplemented with red pigments. Regardless of diet, the difference in patch size between frontalis and griscomi males persisted after moult in captivity. The author concludes that the difference in patch size between frontalis and griscomi males reflects genetic differences between these populations, but that the differences in the mean plumage colouration of males among populations reflect differences in the access that males have to carotenoid pigments during moult.     

中国节腹泥蜂属一新种记述(膜翅目:方头泥蜂科)

记述采自中国海南省的方头泥蜂科Crabronniae、大头泥蜂亚科Philanthinae、节腹泥蜂属Cerceris 1新种:褐节腹泥蜂Cerceris rubigina,sp.nov..模式标本保存在云南农业大学昆虫标本室.     

Female presence affects male behavior and testosterone levels in the European starling (Sturnus vulgaris)

In this study, we confronted individually housed male European starlings (Sturnus vulgaris) with a female conspecific for 60 min to study the consequences on behavior and plasma testosterone (T) concentrations. Control males experienced a similar procedure, the only difference being that they were tested in the absence of a female. Female presence significantly affected both behavior and plasma T levels of male starlings. Experimental males spent significantly more time singing in the nest box and flew significantly more into the nest box with green nesting material during female presentations than during control periods. Control males never showed these mate attraction behaviors. In total 5 of the 16 experimental males did not respond behaviorally to the female stimulus bird (NR males). In contrast to T levels of control males, plasma T concentrations of both experimental males that did respond to the female (R males) and of NR males (which only perceived the female stimulus) were positively influenced by female presentation. The time spent singing in the nest box by experimental males (R and NR males combined) during female presence tended to be positively correlated with changes in plasma T levels. Finally, before introduction of a female, plasma T levels of R males were significantly higher than those of NR males indicating that individually housed males respond to the presence of a female conspecific by increasing their mate attraction behaviors only when a threshold plasma T concentration has been reached.     

Thermoregulation and flight activity in territorial male graylings,Hipparchia semele (Satyridae), and large skippers,Ochlodes venata (Hesperiidae)

Some male butterflies defend specific mating sites, e.g. sandy patches (Hipparchia semele) or plants (Ochlodes venata). When perching within its territory, a male orients the body axis and tilts its wings and body in order to control the body area exposed to the sun, and thereby keeps its body temperature (T _b) as close to a preferred level as possible. In accordance with a model presented here, these behaviours can be separated into three successive phases. At low temperatures, the males maximized the heat load by exposing the maximum body area (sun-basking). This raised T _b above the temperature of a non-regulating animal by c. 3° C. At an intermediate range of temperatures, T _b was kept constant at the preferred level by means of a gradual change of body orientation and posture (graded phase). At high temperatures, the heat load was minimized by exposing the minimum body area. This lowered T _b below that of a non-regulating animal by c. 2.5° C. H. semele went through all three phases, but O. venata only reached the basking phase due to a more moderate microclimate. Three types of thermoregulation in ectothermic animals and their functions are discussed. Thermoregulation in territorial male butterflies serves to prepare the animal for efficient flight performance if another male should try to take over the territory, or a predator attacks. The males also made frequent short flights, spontaneously or elicited by other insects. Their duration was independent of temperature, and they may function as a sexual signal.     

Relevance of mating-associated stimuli, ovulation, and the progesterone receptor for the post-coital inhibition of estrous behavior in the female rabbit

Estrous female domestic rabbits (Oryctolagus cuniculus) display scent marking (“chinning”) and sexual receptivity. Mating induces ovulation, which occurs approximately 12 h later, and also decreases chinning and receptivity. In the present study, we explored the participation of mating-associated stimuli, ovulation, and the progesterone receptor (PR) in mediating such behavioral effects. We found that copulatory stimuli were not necessary, and that ovulation alone was sufficient, as these behavioral changes were replicated in unmated females by intravenous administration of human chorionic gonadotropin (hCG). The post-mating administration (s.c.) of 5 μg/day estradiol benzoate (EB), prevented the decline in chinning and receptivity. A lower dose of EB (1 μg/day) had no effect, nor did the antiprogestin RU486 (20 mg, s.c., administered 3 h before mating). However, the combination of a single pre-mating administration of RU486 plus the post-mating administration of 1 μg/day EB completely blocked the decline in estrous behavior. We propose that PR activation around the time of mating and a post-mating decline in ovarian estradiol secretion and/or estradiol responsiveness act in parallel to terminate estrus in this species.     

On the taxonomy of South African digger wasps of the tribe Oxybelini (Hymenoptera,Crabronidae)

Three South African species of digger wasps of the tribe Oxybelini, initially described in the genus Belomicrus A. Costa, B. (Nototis) bicornutus Arnold, B. (Nototis) crassus Arnold, and B. ferrieri Kohl, are considered to be members of the separate genera Nototis Arnold, 1927, Belarnoldus gen. n., and Belokohlus gen. n., respectively. The new species Nototis falcidens and the previously unknown male of N. bicornutus and female of B. crassus are described. The lectotype of B. ferrieri is designated.     

Nesting biology of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera, Crabronidae) in trap-nests in Southern Brazil.

This study was carried in the Parque Municipal das Araucárias in the municipality of Guarapuava, state of Paraná, Southern Brazil. Three hundred and sixty five nests of T. lactitarse were obtained using trap-nests of 0.7, 1.0, and 1.3 cm in diameter. All of them had similar architecture, regardless of the diameter of the trap-nest. Completed nests consisted of a linear series of brood cells whose average number per nest was of 3.3, 4.0 and 3.6 for the nests with 0.7 cm, 1.0 cm and 1.3 cm in diameter, respectively. They were constructed more often during the summer. T. lactitarse had two types of life cycles: direct development (without diapause), and delayed development (with diapause during winter). Natural enemies included Chrysididae, Sarcophagidae, Dolichopodidae and Ichneumonidae. Out of 1,353 identified spider prey, 1,313 belonged to the Araneidae family.