2′-Hydroxy-4′-methoxyacetophenone (Paeonol) in Exacum affine cv.

Since the lesioned part of the Exacum affine cv. plant showed remarkable insect attractivity to males of the giant danaid butterfly, Idea leuconoe, the volatile components of E. affine cv. were analyzed. The main component in every part was identified as 2′-hydroxy-4′-methoxyacetophenone (paeonol), and authentic paeonol crystals showed similar insect attractivity.     

Permanence and global attractivity for Lotka–Volterra difference systems

 The permanence and global attractivity for two-species difference systems of Lotka–Volterra type are considered. It is proved that a cooperative system cannot be permanent. For a permanent competitive system, the explicit expression of the permanent set E is obtained and sufficient conditions are given to guarantee the global attractivity of the positive equilibrium of the system. Received: 21 May 1997 / Revised version: 25 November 1998     

Food Deprivation and Restriction During late Gestation Affect the Sexual Behavior of Postpartum Female Meadow Voles,Microtus pennsylvanicus

In many species of small mammals, including meadow voles, Microtus pennsylvanicus, females come into postpartum estrus (PPE) within 12–24 h of giving birth, allowing them to mate and become pregnant while raising the current litter. PPE females show increases in attractivity, proceptivity, and receptivity, the three components of sexual behavior, relative to females not in PPE. Several studies have shown that food deprivation and restriction reduce attractivity, proceptivity, and receptivity of females not in PPE. We tested the hypothesis that food deprivation and restriction during late gestation cause deficits and decrease the attractivity, proceptivity, and receptivity of females when they enter PPE. Our data support the hypothesis. On day 1 of lactation, females that were food deprived and food restricted produced scent marks that were significantly less attractive as those produced by control PPE females. Food deprivation but not food restriction caused females to no longer display significant preferences for the scent marks of males over those of females (proceptivity). Food deprivation and food restriction were sufficient to induce females to become significantly less sexually receptive than control females. Eleven of 12 control PPE females mated, 4 of 12 food‐restricted females mated, and 3 of 12 food‐deprived females mated. Dams facing food deprivation or restriction during late gestation may have to balance the benefits of mating during PPE with the increased costs associated with getting pregnant while they are lactating.     

Hormonal control of male courtship behavior and female attractivity in the garter snake (Thamnophis sirtalis sirtalis)

Mating behavior in both intact and gonadectomized garter snakes (Thamnophis sirtalis sirtalis) was measured following hormone administration. Male courtship was androgen-dependent; subcutaneous implants of crystalline testosterone propionate (TP) pellets induced mating behavior within 2 days in both intact, reproductively inactive males and castrated males. Female attractivity, as measured by male courtship of the female, was stimulated by exogenous estrogen; 20 μg/day of estradiol benzoate (EB) was the minimum effective dose for stimulating female attractivity in both intact, reproductively inactive females and ovariectomized females. TP-implanted males selectively courted EB-primed females in both sequential and simultaneous (choice) mating tests. It is probable that males use estrogen-dependent olfactory cues produced by the females to discriminate between hormone- and vehicle-injected females.     

Effects of ovariectomy and estrogen replacement on attractivity and receptivity in the red-sided garter snake (Thamnophis sirtalis parietalis)

Activation of courtship behavior in male red-sided garter snakes, Thamnophis sirtalis parietalis, is independent of the presence of sex steroids. The only consistent treatment that stimulates courtship behavior in males is prolonged exposure to low temperature followed by subsequent warming, mimicking the emergence from hibernation. We investigated whether attractivity and receptivity in female red-sided garter snakes is similarly steroid independent.Female red-sided garter snakes are attractive when they emerge from hibernation and are courted by males; most mate within an hour of emergence. In a series of experiments, groups of females were either ovariectomized (OVEX) in the late spring, fall or while in hibernation. They were tested for attractivity and receptivity upon emergence from hibernation. Females OVEX in the spring were unattractive whereas those OVEX in fall or while in hibernation were attractive. Thus, attractivity appears determined the year before emergence and is dependent on the presence of the ovaries. All OVEX females were unreceptive upon emergence. OVEX females were also given replacement estradiol (E) treatment (either in Silastic capsules or single injections) at various points of their annual cycle. The only treatment that resulted in reinstating receptivity in OVEX females was the injection of E (20 g) one hour prior to emergence. The effectiveness of E in reinstating receptivity was time dependent: the longer the period between emergence and injection, the less effective the same dosage was in stimulating receptive behavior.These experiments suggest that sexual behavior in female red-sided garter snakes is, unlike males, dependent on the presence sex steroid hormones. Although E is naturally at its lowest seasonal level upon emergence, the concentration is sufficient to stimulate receptivity. However, it appears that temperature regulates a time-limited window of sensitivity to E.     

The inhibition of female rabbit sexual behavior by progesterone: progesterone receptor-dependent and-independent effects

In the pregnant domestic rabbit, scent marking (“chinning”) and sexual behavior are inhibited by ovarian-derived progesterone (P). In order to distinguish behavioral effects of P that are PR-dependent from those mediated by its ring A reduced metabolites, we administered P, P+RU486 (PR antagonist), chlormadinone acetate (CA, synthetic progestin that does not form ring A reduced metabolites), or vehicle to ovariectomized (ovx) estradiol-benzoate (EB)-treated female rabbits, via sc injection, on experimental day 0. Chinning was quantified daily, and mating tests were done on days -1, 1, 3, 5, and 7. On day 1, chinning was significantly decreased, and the latency to be mounted by the male was significantly increased (indicating decreased sexual attractivity of the female) in P-treated females. The effect of P on chinning, but not its effect on sexual attractivity, was completely blocked by RU486 and replicated by CA. Although CA had no effect on attractivity on day 1, it decreased both sexual receptivity and attractivity on day 3. In a preference test in which the male could interact with either an ovx EB-treated female or an ovx female that had received one of the above hormone treatments 24 h earlier, P decreased sexual attractivity and increased aggression. The effect of P on aggression, but not its effect on attractivity, was blocked by RU486 and replicated by CA. These results indicate that both PR-dependent and PR-independent mechanisms decrease sexual attractivity, whereas PR activation is necessary for the inhibition of chinning and sexual receptivity, and for the stimulation of aggression.     

Global stability in chemostat-type plankton models with delayed nutrient recycling

 In this paper, we consider chemostat-type plankton models in which plankton feeds on a limiting nutrient and the nutrient is supplied at a constant rate and is partially recycled after the death of plankton by bacterial decomposition. We use a distributed delay to describe nutrient recycling and a discrete delay to model the planktonic growth response to nutrient uptake. When one or both delays occur, by constructing Liapunov functionals, we obtain some sufficient conditions for the global attractivity of the positive equilibrium, which can be regarded as estimates of the delays for persistence of global attractivity. Received: 9 January 1996 / Revised version: 1 October 1997     

The behavior of the larch casebearer (<Emphasis Type="Italic">Protocryptis sibiricella</Emphasis>, Lepidoptera,Coleophoridae) in sustained outbreak sites: Communication 2

During a study of the larch casebearer Protocryptis sibiricella (Falkovitsh, 1964) in a forest-steppe larch forest of the Kuznetsk Alatau foothills, the existence of its sustained outbreaks was for the first time shown to depend on the behavior of adults during oviposition. The dispersal distance of the adults was experimentally assessed. The females preferred to lay eggs on the larch needles already damaged by the same species. The attractivity of needles damaged naturally by the pest and artificially was compared.     

Responses of male winter moths (Operophtera brumata) to their sex attactant (3Z,6Z,9Z)-1,3,6,9 nonadecatetraene and to some structural analogues

Conclusion (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene, the synthetic sex pheromone of the female of O. brumata is highly active in attracting males of this species in the field (Germany and Switzerland). No analogous compounds possessing attractivity to O. brumata males have been found up to now, nor did they show any inhibitory effects to the same species.Therefore (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene (I) can be recommended as a good attractant in the prognosis or monitoring of this lepidopteran pest.     

Psychosocial stress suppresses attractivity, proceptivity and pulsatile LH secretion in the ewe

Various stressors suppress pulsatile secretion of luteinizing hormone (LH) in ewes and cortisol has been shown to be a mediator of this effect under various conditions. In contrast, little is known about the impact of stress and cortisol on sexual behavior in the ewe. Therefore, we tested the hypothesis that both psychosocial stress and stress-like levels of cortisol will reduce the level of attractivity, proceptivity and receptivity in addition to suppressing LH secretion in the ewe. In Experiment 1, a layered stress paradigm of psychosocial stress was used, consisting of isolation for 4 h with the addition of restraint, blindfold and noise of a barking dog (predator stress) at hourly intervals. This stress paradigm reduced LH pulse amplitude in ovariectomized ewes. In Experiment 2, ovariectomized ewes were artificially induced into estrus with progesterone and estradiol benzoate treatment and the layered stress paradigm was applied. LH was measured and sexual behavior was assessed using T-mazes and mating tests. Stress reduced pulsatile LH secretion, and also reduced attractivity and proceptivity of ewes but had no effect on receptivity. In Experiment 3, ewes artificially induced into estrus were infused with cortisol for 30 h. Cortisol elevated circulating plasma concentrations of cortisol, delayed the onset of estrus and resulted in increased circling behavior of ewes (i.e. moderate avoidance) during estrus and increased investigation and courtship from rams. There was no effect of cortisol on attractivity, proceptivity or receptivity during estrus. We conclude that psychosocial stress inhibits LH secretion, the ability of ewes to attract rams (attractivity) and the motivation of ewes to seek rams and initiate mating (proceptivity), but cortisol is unlikely to be the principal mediator of these effects.     

The potential effect of high atmospheric CO2 on soil fungi–invertebrate interactions

Litter mixtures of four meadow plant species, Cardamine hirsuta, Poa annua, Senecio vulgaris, and Spergula arvensis, were produced from laboratory model terrestrial ecosystems maintained at either ambient or enriched (ambient + 200 µmol mol^?1) CO₂ concentrations. The effect of litter source on the oviposition attractivity of fungi to the sciarid fly Lycoriella ingenua was tested for seven fungal species (Absidia glauca, Cladosporium cladosporioides, C. herbarum, Fusarium oxysporum, Penicillium arenicola, P. chrysogenum, and P. janthinellum). For all species, except F. oxysporum, oviposition attractivity increased when the fungi were growing on litter derived from CO₂‐enriched environments. The relative increase of the oviposition attractiveness of fungi growing on CO₂‐enriched litter differed substantially and resulted in a shift in sciarid fly oviposition preference. For example, when P. chrysogenum and C. herbarum grew on ambient litter, P. chrysogenum was more attractive; the opposite was true for mycelia growing on enriched litter. The effect of litter source on the suitability of four fungal species for larval development was also tested. In two species of fungi (A. glauca and C. herbarum) suitability was significantly higher if growing on CO₂‐enriched litter. With P. chrysogenum the opposite was true. The consequences of these rarely considered CO₂‐induced trophic interactions on ecosystem processes such as nutrient feedback cycles between plants and soil decomposition are considered.     

Attraction of the fungus gnat Bradysia optata to cantharidin

The toxic terpenoid cantharidin has been reported to attract some specimens of undetermined fungus gnats. In order to investigate this phenomenon, the fungus gnat Bradysia optata Rudzinski, 1994 (Diptera: Sciaridae) was reared and its attraction to cantharidin was registered. Significant attractivity of the substance to males could be confirmed with both sticky baits in a greenhouse and an olfactometer under laboratory conditions. Ingestion of the toxic compound for chemical defence, which has been shown for some so-called canthariphilous insects, was not observed. However, a high toxicity of cantharidin for the attracted species B. optata could be demonstrated. These unusual findings could be the result of the mycetophagous sciarids mistaking the terpenoid for certain structurally related fungal metabolites. These secondary metabolites might indicate a convenient meeting-place for mating and oviposition.     

Sex Pheromone of the Female Large Cabbage-heart Caterpillar,Crocidolomia binotalis Zeller (Lepidoptera: Pyralidae)

Sex pheromone components of the female Crocidolomia binotalis, an insect pest of cabbages in Indonesia, were identified from the ovipositor tip extract of virgin females by analyzing with chromatographic fractionation and capillary GC/MS. In an EAG response and attractivity test with a wind tunnel system, a mixture of synthetic compounds, (Z)-9-tetradecenyl acetate (Z-9- TDA) and (Z)-l 1-hexadecenyl acetate (Z-ll-HDA), in the ratio of 1:7—1:60 and an amount of 1 ~ 50 ng on a filter paper, showed strong activities comparable to the activity of the ovipositor tip extract, which contained the two compounds at a ratio of c. 1:10 (Z-9-TDA : Z-l 1-HDA). The mixture of these two compounds might be the sex pheromone of C. binotalis.     

Changes in female attractivity and proceptivity throughout the oestrous cycle of the Syrian hamster (Mesocricetus auratus)

Interactions between male and female hamsters were recorded on each day of the oestrous cycle in terms of proximity (approaching, leaving and following by each member of the pair). Time spent sniffing the partner was also recorded. Measures were extracted which related to the females' stimulus value to the male (attractivity) and to the females' initiation and maintenance of proximity to the male (proceptivity). Both were found to change not only at oestrus but throughout the three dioestrous days of the cycle. Although the concepts of attractivity and proceptivity were originally introduced in relation to the oestrous female (Beach 1976) their extension to the dioestrous period may lead to a better understanding of the social and sexual factors underlying the interaction.     

What Females Tell Males About Their Reproductive Status: Are Morphological and Behavioural Cues Reliable Signals of Ovulation in Bonobos (Pan paniscus)?

In many Old World primate species, female attractivity increases during the tumescent phase of the sexual swelling for a period that lasts considerably longer than oestrus‐related attractivity in other mammals. We examined the reliability of the swelling as an indicator of ovulation in captive bonobos, a species with a long and variable phase of maximum tumescence. Using a combined approach of (1) observations of sexual behaviour, (2) visual scoring of the sexual swelling and (3) analysis of faecal progestin to assess the timing of ovulation during 23 ovulatory cycles of eight adult females, we found that in 30% of these cycles the presumed day of ovulation did not fall within the period of maximum tumescence. When ovulation did occur during maximum swelling, it was more closely related to the end rather than the onset of the maximum swelling period. However, the pattern of sexual swelling was not a reliable indicator of ovulation. In addition, sexual behaviour of both sexes increased in frequency with the degree of the swelling but not around the time of ovulation. We conclude that swellings in bonobos provide honest information on the probability of ovulation, but not its exact timing, and that therefore the `obvious ovulation'‐hypothesis cannot explain the function of sexual swellings in bonobos.     

Attractivity of coherent manifolds in metapopulation models

The likelihood that coupled dynamical systems will completely synchronize, or become “coherent”, is often of great applied interest. Previous work has established conditions for local stability of coherent solutions and global attractivity of coherent manifolds in a variety of spatially explicit models. We consider models of communities coupled by dispersal and explore intermediate regimes in which it can be shown that states in phase space regions of positive measure are attracted to coherent solutions. Our methods yield rigorous and practically useful coherence criteria that facilitate useful analyses of ecological and epidemiological problems.     

Attractivity of male and female rats which are hormonally manipulated during early development and in adulthood

Attractivity is one aspect of female sexuality relevant for the understanding of male-female sexual interactions. In a previous study, it was shown that intact males were equally attracted to early androgenized, gonadally intact females as to normally developed, estrous females. The present study was designed to investigate in what way hormones given in adulthood might influence attractivity of early androgenized females in adulthood. Specifically, we compared the attractivity of neonatally androgenized females (NeoTP) to the attractivity of normally developed females (NeoOIL), neonatally castrated males (NeoCASTR), and neonatally sham-castrated males (NeoSHAM) when different groups received either OIL, estradiol benzoate (EB) or testosterone propionate (TP) in adulthood. The male's preference to stay in the vicinity of one incentive in favor of the other was taken as an index of attractivity. The results show that, under the present hormonal conditions, NeoTP-females are generally less attractive than NeoOIL-females, more attractive than NeoSHAM-males, and equally attractive as NeoCASTR-males. TP-treated androgenized females were found to be equally attractive as TP-treated NeoSHAM-males. It is concluded that, relative to normally developed females, androgenized females become less attractive when the endogenous secretion of sex steroids is artifically controlled by gonadectomy and/or by administration of fixed amounts of sex steroids.     

Response of female Lutzomyia longipalpis to host odour kairomones from human skin

Lutzomyia longipalpis Lutz & Neiva (Diptera: Psychodidae) is the vector of Leishmania chagasi, the aetiologic agent of visceral leishmaniasis in the New World. In the present study, the response of female sandflies from Jacobina, Brazil, to human odours from six different volunteers was investigated. Glass Petri dishes were handled by different volunteers and then exposed to female sandflies. There was a significant difference between subjects in that some individuals were more attractive or less repellent to sandflies. Response of flies to handled Petri dishes was higher during the first minutes of observation, suggesting the presence of volatile compounds in hand odours. Extracts of glass Petri dishes that had been handled by the volunteers were made with organic solvents such as acetone, methanol, pentane and ether. These were then concentrated and tested for sandfly response. Only extracts carried out with non-polar solvents such as pentane and ether were able to transfer odours from handled glass Petri dishes onto clean dishes. The attractivity of male and female human subjects was monitored for 80 days, and minor fluctuations in attractiveness were observed.     

Sex pheromones of Phyllonorycter acerifoliella and Ph. heegerella and communication peculiarities in three species of leafmining moths

Females of the leaf miner moth Phyllonorycter acerifoliella (Z.) [=Ph. sylvella (Hw.)] and Ph. heegerella (Z.) (Lepidoptera: Gracillariidae: Lithocolletinae) release their sex pheromone at the beginning of photophase. The periodicity of the `calling' behaviour of Ph. acerifoliella females was established. Three compounds from calling virgin Ph. heegerella females were collected by the Solid Phase Micro Extraction (SPME) technique and identified as (Z)-8-tetradecenyl acetate (Z8-14:OAc), tetradecyl acetate (14:OAc) and (Z)-8-tetradecenol (Z8-14:OH) in the ratio (88±3):(2±0.6):(10±5) by capillary gas chromatography and mass spectrometry. Field trapping experiments demonstrated that the first two compounds are important for the attraction of conspecific males. Z8-14:OAc was found to be attractive when tested separately, while 14:OAc acted as synergist. The attractivity of the three component blend was reduced by 10% admixture of either (E)-10-dodecenyl acetate (E10-12:OAc) or (Z)-10-tetradecenyl acetate (Z10-14:OAc).Field tests of Z10-, Z8- and E10-14:OAc, identified from Ph. acerifoliella females, demonstrated that the first two compounds were essential for the attraction of conspecific males; so both are sex pheromone components. The attractivity of the three component blend of Z10- Z8- and E10-14:OAc was reduced by 10% admixture of (E)-10-dodecenol (E10-12:OH). The following four semiochemical compounds, Z8-14:OAc, Z8-14:OH, E10-14:OAc and 14:OAc, identified from phyllonoryctid females, as well as two sex attraction antagonists for Ph. acerifoliella and Ph. heegerella males, E10-12:OAc and Z10-14:OAc, are new for the family Gracillariidae. The results of field trapping experiments revealed mechanisms ensuring the specificity of the chemocommunication systems in Ph. acerifoliella, Ph. heegerella and Ph. ulmifoliella (Hb.) moths.     

Aggregation behaviour and interspecific relationships in Dermaptera

The rate of gregariousness and intra- and inter-specific attractivity were evaluated under laboratory conditions in five species of Dermaptera. The three species of the genus Forficula (Forficula auricularia L., F. decipiens Gené and F. pubescens Gené) showed distinctly gregarious behaviour in old larvae and adults in the pre-reproductive phase. This gregariousness was seen at the intraspecific level and also among individuals of different species. The other two species, Labidura riparia Pallas and Euborellia moesta Gené, were randomly distributed over the available shelters, with no distinct tendency for aggregation or isolation. In individual tests, insects of all five species were attracted by shelters previously visited by conspecifics in preference to control shelters. For the two non-gregarious species, this phenomenon might function as a burrow marker. The same tests showed an interattractivity for four of the species studied. Only L. riparia did not respond to the trails of the four other species, although its trails were attractive to the other species. The pheromonal nature of the substances involved in the interspecific relationships and the involvement of behaviour in the biology and speciation of Dermaptera are discussed.