Possible Presence of Pheromone in Mating Behavior of the Pine Sawyer Monochamus saltuarius Gebler (Coleoptera: Cerambycidae)

The mating behavior of the pine sawyer, Monochamus saltuarius, is composed of two phases. The first phase is the female approach to pheromone-releasing males. When bioassayed by T-tube olfactometer, the female was moved toward the male and hexane extract of the male. The second phase is the male mounted the female to copulate after perceiving the contact pheromone being on the female body surface. When the hexane extract of the female body surface was applied onto a glass rod (dummy), the male showed the mating behavior to the dummy. The component of female body surface extract fractionated using a silicic acid column elicited mating behaviors of the males, and the other component by ether fraction was showed a high copulatory attempt. This study was discussed two-step functions of the pheromones in the beetle mating behavior.     

Sperm numbers,their storage and usage in the fly Dryomyza anilis

In the fly Dryomyza anilis females have two kinds of sperm storage organs: one bursa copulatrix and three spermathecae (two spermathecae with a common duct form the doublet, and the third is a singlet spermathecal unit). At the beginning of a mating the male deposits his sperm in the bursa copulatrix. After sperm transfer the male taps the female''s abdomen with his claspers. This behaviour has been shown to increase the male''s fertilization success. After mating, the female discharges large quantities of sperm before oviposition. To find out where the sperm remaining in the female are stored, I counted the number of sperm in the droplet and in the female''s sperm storage organs after different types of mating. I carried out three mating experiments. In experiment 1, virgin females were mated with one male and the matings were interrupted either immediately after sperm transfer or after several tapping sequences. The results show that during male tapping more sperm moved into the singlet spermatheca. In addition, the total number of sperm correlated with sperm numbers in all sperm storage organs, and male size was positively related to the number of sperm remaining in the bursa. In experiment 2, females mated with several males. The number of sperm increased with increasing number of matings only in the doublet spermatheca. No increase in the number of sperm in the singlet spermatheca during consecutive matings suggests that sperm were replaced or did not reach this sperm storage organ. In experiment 3, virgin females were mated with a single male and half of them were allowed to lay eggs. The experiment showed that during egglaying, females primarily used sperm from their singlet spermatheca. The results from the three experiments suggest that sperm stored in the singlet spermatheca is central for male fertilization success and male tapping is related to sperm storage in the singlet spermatheca. The different female''s sperm storage organs in D. anilis may have separate functions during sperm storage as well as during sperm usage.     

Reproductive behavior of free-ranging Lemur catta at Beza Mahafaly Special Reserve,Madagascar

Observations of reproductive behavior in free-ranging Lemur catta were carried out during one annual cycle. Variability in the behavior of female ringtailed lemurs during parturition appears to be mainly a function of the female's parity and thus her experience. Females within a troop show estrous asynchrony and characteristically mate with more than one male. Females also exhibit proceptive behavior toward and mate with some males from other troops and with transferring males. The potential for a male to monopolize mating opportunities during a female's short estrous period is therefore limited. Male mating strategies in ringtailed lemurs can be seen as adaptations to female mate choice during a highly restricted breeding season. In this species the dominance hierarchy does not break down with regard to the order of mating. The highest ranking male (central male) mates first and shows precopulatory guarding and longer postejaculatory guarding, which may increase his chances of siring the offspring. Subsequent mating partners have developed various counterstrategies to mitigate mating order effects.     

Mutual mate choice by mountain pine beetles: size‐dependence but not size‐assortative mating

1. Mutual mate choice may be rare, occurring when both sexes invest heavily in reproduction, mating opportunities are abundant, and individuals differ in quality. 2. Mountain pine beetles, Dendroctonus ponderosae (Curculionidae: Scolytinae) appear to meet the conditions for mutual mate choice. We introduced males to females in breeding sites and observed the occurrence and speed of a male entering a female's gallery. We tested for consequences of mutual mate choice, namely condition‐dependent choosiness and assortative mating. 3. Males were more likely to enter a female's gallery when the gallery was in a smaller tree with less resin production and when the gallery was larger. Female body size and condition did not influence the probability of entry. Larger males were less likely to enter a gallery than were smaller males, probably because of size‐dependent choosiness rather than physical limitations. 4. Small males took longer to enter galleries of large females than of small females, whereas large males entered as quickly into galleries of large females as small females. This suggests size‐dependent choosiness by females. 5. No assortative mating by body size was detected, probably because males appeared to choose on the basis of female‐associated resources rather than on female traits.     

Beobachtungen zum Paarungs- und Aufzuchtverhalten der Wasserspitzmaus Neomys fodiens (Soricidae)

Five European Water Shrews (Neomys fodiens) were kept in an indoor enclosure of 2.7 m² where one couple mated regularly. Multiple copulations appeared over a period of about 12 hours. Ten litters with 56 offspring were born and 33 survived. The female gave birth to her latest litter at an age of about 20 month, 2 month later as the end of the reported lifespan in nature. The period of fertility lasted 336 days and is comparable to those of Crocidura. At the end of this period three times signs of pseudopregnancy were detected: After copulating the female started building her nest and intensified this behaviour after about three weeks, at the end of the expected “gestation” swollen nipples could also be noticed, but no offspring inside the nest. The female died at an age of about 38 month.After successful copulations a copulatory lock was achieved and the female could track her mate. The mating behaviour can be classified as follows: a) male entering female's territory, b) precopulatory chasing, c) approaching of the mates, d) mounting and repeated copulations attempts, e) successful copulation, male slipping down from female's back, f) copulatory lock and resting, g) cleaning sexual organs, h) continuing chasing and further copulations or i) displacing the male and finishing sexual behaviour. Driving off the male from female's territory could last some time. No special calls were uttered in the close context of copulatory behaviour, only the known ones while chasing, some low contact calls inside the nest and aggressive calls while driving off the male.     

Breeding Strategies in Females of the Parasitoid Wasp Spalangia endius: Effects of Mating Status and Size

Does the mating status or body size of a female parasitoid wasp affect her host size choice or propensity to burrow? In Spalangia endius, using smaller hosts appears to reduce a female's cost of parasitization but not her son's fitness. However, virgin females, which produce only sons, did not preferentially parasitize smaller hosts. Mated females also showed no host size preference. Mated females burrowed more than virgins in the presence of hosts, although not in their absence. Burrowing may reduce a mated female's harassment from males, and not burrowing may increase a virgin female's chance of mating because males avoid burrowing. Mating did not increase female longevity. Greater female size increased the offspring production of mated females burrowing for hosts but not in the absence of burrowing and not in virgin females. A female's size had no significant effect on whether her first drill attempt was on a large or a small host or on the duration of her successful drills.     

Female behavioral strategies during consortship in Tibetan macaques (Macaca thibetana)

Consortship has been defined as a temporary association between an adult male and an estrous/receptive female. It has been considered as male mating strategies to improve male mating success and potential reproductive success. However, the female roles have been more or less neglected, and thus, less is known about female behavioral strategies during the consortship periods. In this study, during the two consecutive mating seasons, we collected behavioral data of free‐ranging Tibetan macaques (Macaca thibetana) habituated in Mt. Huangshan, China, to investigate female behaviors when she was consorted by an adult male. The results showed that (a) females were more likely to approach and exhibit sexual solicitation to their consorting males during the consorted period, and females also exhibited less approach to their nonconsorting males; (b) females exhibited strong responses (either departed distantly or formed affiliative relationships with their consorting male partner) when their consorting males mated with rival females or showed sexual motivation toward rival females; (c) female preferences were positively correlated to the duration of consortships and the frequencies of ejaculation copulations, independent of the social ranks of their consorting male partners. Our results suggested that female strategies played much more important roles in forming and maintaining consortship than previously assumed. It provides new insight into understanding female adaptive strategies to male strategies by forming consortships in multimale–multifemale primate species when males could not identify female''s fertile phase accurately.     

Coevolution of non-fertile sperm and female receptivity in a butterfly

Sexual conflict can promote rapid evolution of male and female reproductive traits. Males of many polyandrous butterflies transfer nutrients at mating that enhances female fecundity, but generates sexual conflict over female remating due to sperm competition. Butterflies produce both normal fertilizing sperm and large numbers of non-fertile sperm. In the green-veined white butterfly, Pieris napi, non-fertile sperm fill the females'' sperm storage organ, switching off receptivity and thereby reducing female remating. There is genetic variation in the number of non-fertile sperm stored, which directly relates to the female''s refractory period. There is also genetic variation in males'' sperm production. Here, we show that females'' refractory period and males'' sperm production are genetically correlated using quantitative genetic and selection experiments. Thus selection on male manipulation may increase the frequency of susceptible females to such manipulations as a correlated response and vice versa.     

Sperm competition and the significance of female multiple mating in the predatory miteParasitus fimetorum

Females of the predatory miteParasitus fimetorum (Gamasida; Parasitina) inhabiting animal manure indiscriminately copulate with many mates. The sperm competition between the males was estimated by electrophoresis of allozymes and the effects of multiple mating on female reproduction were investigated. When females were forced to mate only once, their fecundity decreased drastically compared to the case of multiple mating (but longevity was unaffected). When one female mated with two males, the outcome of sperm competition depended greatly upon the mating interval. When the second mating occurred immediately after the first, the female fecundity decreased as in the case of single mating and the second male fertilized only a few eggs. However, when there was an interval of 1 day between the two matings, the females achieved normal fecundity and the second male fertilized approximately half the eggs. This suggests that the spermatophore deposited by the first male may act as a short-term copulatory ‘plug’ in the female's genital opening. When one female mated with several males with 1 day intervals, three or more males shared fertilization of the eggs. This study suggests that the multiple mating of females is a necessary stimulus to continue oogenesis and some physiological factors for this stimulation may exist in spermatophores.     

The morphology of mating plugs and its formation in scorpions: Implications for intersexual participation

Mating plugs have been proposed as a mechanism that has evolved to avoid sperm competition. Their structure and composition vary across taxa and are related to the effectiveness of its function. This effectiveness could be related to different evolutionary interests of the sexes. Urophonius brachycentrus and Urophonius achalensis (Scorpiones, Bothriuridae) are highly suitable species to study mating plugs because both are monandrous species with specific morphological and physiological responses in the female's genitalia. Here, we analyze (a) the morphology and fine structure of the mating plugs of both species, (b) the site of production in males and the formation process of the mating plug, and (c) the changes that it undergoes over time in the female's reproductive tract. In both species, a complex mating plug obliterates the female's genital aperture and fills the genital atrium. We observed considerable interspecific variation in the mating plug morphology. A mating hemi-plug was found surrounding the capsular lobes of the hemispermatophore, which could have a mixed composition (involving portions of the hemispermatophore and glandular products). The glandular portion was transferred in a semi-solid state filling the female's genital atrium and then hardening. Changes that the plug undergoes in the female's genitalia (darkening and increase of the “distal” area of the plug) indicate a participation of the female to the formation of this type of plug. Our study provides new insights into the plugging phenomenon in scorpions, and we discussed the adaptive significance as a post-copulatory mechanism to avoid sperm competition.     

松墨天牛成虫体内的松材线虫分布和速检研究

为了探索快速测定松墨天牛成虫(下称成虫)的带疫性,用解剖方法和自制便携式显微镜,对成虫携带的松材线虫部位和速检(下称线虫)作了研究,得到下列结果：87．9％的线虫分布在成虫的节间、腹腔和生殖器内;雄成虫阳茎是松材线虫集中分布区,两头平均携带线虫498．5条;交尾时雄成虫把阳茎上的线虫传到雌成虫外生殖器,在雌成虫产卵时再把线虫带入松树形成层组织;在野外检测成虫带疫性平均需时1．57min。     

All that Glisters is not Gold: Sensory Bias, Sexual Conflict and Nuptial Feeding in Insects and Spiders

It is becoming increasingly clear that the evolutionary interests of the sexes are often in conflict when it comes to mating. Sexual encounters involving nuptial gifts, however, have often been viewed as prime examples of sexual co‐operation, rather than conflict. In this review, I explore the proposition that nuptial gifts act as sensory traps: by exploiting the female's gustatory responses, the male may be able to entice females to accept superfluous matings and/or transfer greater volumes of ejaculate than are in the female's reproductive interests. Evidence suggests that the females’ sensory biases may have played an important role in shaping gift characteristics in at least four different systems, although relatively few forms of nuptial feeding have so far been examined from this perspective. I argue that gift composition is more likely to be tailored to increasing the attractiveness of the gift to the female and/or maximizing gift handling time than to suit the female's nutritional needs and that the fecundity‐enhancing benefits of nuptial gifts are often questionable and have been over‐stated in the literature. Fertilization biases associated with the female's attraction to the nuptial gift, however, could lead to in‐direct benefits for the female. On the other hand, nuptial feeding may also lead to significant costs to the female. Evidence suggests that some types of gift entice the female to mate, but it is not clear whether the resultant degree of polyandry is higher than optimal for the female. In other cases, evidence suggests that the gift enables the male to overcome the resistance of the female to accepting an extra large ejaculate and that large ejaculates are associated with longer post‐mating sexual refractory periods in the female. This could represent a cost to the female by delaying or preventing her from receiving the genetic benefits of polyandry. At present, it is not clear, however, whether such costs outweigh the potential benefits of nuptial feeding for the female.     

SPERM COMPETITION AND THE EVOLUTION OF NUPTIAL FEEDING BEHAVIOR IN THE CRICKET,GRYLLODES SUPPLICANS (WALKER)

The pattern of sperm predominance in doubly mated female crickets, Gryllodes supplicans, was investigated using a radiation-sterility technique. Female G. supplicans made significant use of sperm from both males in fertilizing eggs; overall, first males to mate enjoyed a small advantage, fertilizing about 60% of the offspring produced subsequent to the second mating. The combined use of the sperm of both males in fertilizing eggs occurred soon after the second mating; evidently, mixing of ejaculates within a female's spermatheca does occur. Male G. supplicans provide females with a nuptial gift, the spermatophylax, which influences the time at which a female removes the externally attached sperm-ampulla; this in turn determines the quantity of sperm that is transferred. Moreover, the degree of sperm precedence achieved by a male may be positively related to the time at which the female removes his sperm ampulla. Thus males, by feeding females, ensure not only that a sufficient number of sperm are transferred to fertilize all of a female's eggs, but also may increase the certainty of their paternity. In mating systems in which females control sperm transfer and paternity is influenced by numbers of sperm (i.e., numerical sperm competition), an increase in prezygotic investment in females may be an adaptive male response.     

Opportunities for female choice in the bed bug Cimex lectularius

Bed bugs are cited as exemplars of sexual conflict because mating can only occur via traumatic insemination. However, past antagonistic coevolution between the sexes does not necessarily preclude current female choice. Here, we investigate opportunities for precopulatory female choice in bed bugs. We examined whether females seek out mating opportunities when they gain the most benefit: when females are virgin and/or have recently fed. But, we found that female mating and feeding status had little effect on female attraction to males and male odor. To determine whether females approach male harborages (home crevices) to seek matings in nature, we investigated where matings occurred among unfamiliar pairs of bed bugs. We found that, despite female attraction to male odor, matings were most likely to take place in the female's harborage rather than the male's harborage. We also examined the effect of feeding on male and female ability to mate. Whereas previous research reported that engorgement impaired female ability to refuse matings, we found that male feeding status had a larger effect on the success of mating encounters than female feeding status. Fed males had poor mating success, suggesting that males may be faced with a trade‐off between mating and feeding.     

Transfer of male secretions from the spermatophore to the female insect in Caryedon serratus (Ol.): Analysis of the possible trophic role of these secretions

In Caryedon serratus (Coleoptra; Bruchidae) a large spermatophore is deposited into the female bursa copulatrix during mating. After mating, the size of the spermatophore decreases and the central part becomes vacuolated. Electrophoretic studies show quantitative but not qualitative modifications of the spermatophore secretions. Within 24 h after mating, some male secretions are transferred from the spermatophore to the haemolymph of females as shown by immunoblotting and autoradiographic studies. Some of these secretions or their derivatives are observed in mature oöcytes. This production constitutes a heavy investment on the part of the males. Mating stimulates vitellogenesis and egg laying and it is possible that the male investment represents a contribution to ovarian production. In the absence of food during imaginal life, the number of matings influences the female's reproductive capacity. The supply of male secretions thus constitutes an important trophic contribution that increases females' fecundity and vitellogenesis. In the presence of food (pollen), repetitive matings do not influence the female's reproduction level. The influence of this trophic source and the extent of its importance are analyzed in this study.     

Transmission of the Pinewood Nematode, Bursaphelenchus xylophilus,to Slash Pine Trees and Log Bolts by a Cerambycid Beetle,Monochamus titillator, in Florida

Field-collected adults of the southern pine sawyer, Monochamus titillator (F.) (Coleoptera: Cerambycidae), naturally infested with fourth-stage juveniles (dauerlarvae) of the pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer, 1934) Nickle, 1970, were maturation fed on excised shoots of typical slash pine, Pinus elliottii Engelm. var elliottii, for 21 days. During August 1981, a male and female adult beetle were held in a sleeve cage placed on the terminal of a side branch of each of seven replicate, healthy 10-year-old slash pine trees. All seven branch terminals showed evidence of beetle feeding on the bark after 1 week, and pinewood nematodes were present in wood samples taken near these feeding sites. Four of the seven trees showed wilt symptoms in 4-6 weeks and died about 9 weeks after beetle feeding. Pinewood nematodes were recovered from the roots and trunks of the dead trees. Each of seven replicate slash pine log bolts was enclosed in a jar with a pair of the same beetles used in the sleeve cages. After 1 week, wood underlying beetle oviposition sites in the bark of all replicate log bolts was infested with the pinewood nematode.     

Female choice of matings to maximise parental care.

We address the question of how many males a female should mate with in the context of species in which males provide care for potential offspring. Our analysis is based on the evolutionarily stable levels of parental effort of a female and a group of males. In the case of one female and two males we give a complete analysis of how the female''s preference for monogamy or polyandry depends on the fitness functions assumed in the model. We then go on to consider the question of how many males a female should mate with to receive the highest level of male care. Our results are relevant in particular to the mating system of the dunnock (Prunella modularis) and also to the general question of whether a species should be monogamous as opposed to polyandrous.     

Cyclic proceptivity in a captive female orang-utan (Pongo Pygmaeus Abelii)

An adult male—female pair of orang-utans was observed for a 3-month period, commencing with the introduction of the animals to each other. After approximately 2 weeks, the female began to show proceptive behaviors towards the male. Two other proceptive periods were observed, occuring from 26 to 30 days apart, and lasting for 4–6 days. These female-initiated periods of sexual activity began with increased locomotor activity, solitary play, proximity to the male, following the male, and social grooming. The peak periods of proceptive behaviour included hand—genital contact, mouth—genital contact, rolling the male onto his back, both dorso-ventral and ventro-ventral mounting, and pelvic thrusting. Although hormonal levels could not be assessed in this study, it is believed that these peaks coincided with ovulation. In previous reports, the presence of proceptive behaviors was perhaps over-shadowed by highly aggressive sexual behavior on the part of male orang-utans. The visibility of proceptivity in this study is attributed to the large cage which allowed the female to escape the male's advances, enabled distance between the animals when they preferred it, and continuous exposure of the orangs to each other. This female orang-utan behavior was compared to the female sexual behaviours of the other great ape species — the chimpanzee and the gorilla.     

Olfactory Sex Attraction and Mating Behaviour in the Pine Sawyer Monochamus galloprovincialis (Coleoptera: Cerambycidae)

The pine sawyer Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is a vector of the pine wood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle. Male and females of this species have a kairomonal attraction to host volatiles and Ips semiochemicals. Once on the host tree, males and females copulate and oviposition occurs. Bioassays using Y-tube olfactometry revealed that females were attracted to volatile compounds produced by males, but not to volatiles produced by females. However, immature males did not seem to release attractants for mature females and immature females did not show any attraction for mature males. A experiment designed to know about mating behaviour in this specie revealed that most of the males encountered females while they were walking. In all pairs both sexes contacted with antennae before copulation, however, in some occasions copulation did not proceed just after antennal contact. On the contrary, in all pairs observed, the male licked the elytra of the female with his mouth palpi just before copulation (licking); immediately afterwards, the male grabbed the female with his forelegs and mounted her suggesting a chemically mediated mate recognition by males.