Patterns Of Reproductive Activity Research Articles

Reproductive Behavior of Paraglenea fortunei (Coleoptera: Cerambycidae)

The daily reproductive activity patterns, reproductive behavior, and stridulation of the beetle Paraglenea fortunei Saunders were studied. There are two activity peaks in walking/flying (0600-1400 hours and 1500-2100 hours) during the day. The peaks for feeding, mating, and ovipositing are 1400-2100 hours, 0800-1500 hours, and 1400-2000 hours, respectively. Feeding and mating usually occur on the upper sections of the plants. The female oviposits in the stem up to 3 cm above ground level and never deposits her eggs where eggs have been deposited by another. Within 10 cm two individuals can communicate through substrate-borne vibrations produced by feeding or walking. A male can discern the sex of another individual from just within 5 cm. Before mating the male always approaches the female, who therefore seems to possess a sex pheromone. Mating may be terminated if the female performs a rejection display on her own initiative, or if another male disturbs the mating pair. Our interpretation of the male's stridulation is defensive behavior, aggressive behavior, a complicated form of courtship display with some slight threat, and a calming of the female to make continuous copulation possible. The female's stridulation may be significant as defensive behavior, rejecting the male's courtship, and a signal for termination of copulation.

Daily Patterns of Reproductive Activity and the Influence of Adult Density and Exposure to Host Plants on Reproduction in the Diamondback Moth (Lepidoptera: Plutellidae)

Daily patterns of activity and the effects of adult density and exposure to host plants on the onset of reproductive activities and age-specific fecundity of the diamondback moth, Plutella xylostella (L.), were determined under constant conditions of 21°C, 70%RH, and a 16:8 (L:D) photoperiod. More than 50% of adult emergence occurred in the first 8 h of the photophase. Although calling occurred throughout the scotophase, >70% of mating and oviposition took place in the first 4 h. Approximately 90% of females had begun to call, mate, and lay eggs, and the females contained ≥1 mature egg by night 4 when kept with males and host plants in individual pairs. In contrast, only 27% of females kept with males but without host plants had mated by night 4, and only 64% contained mature eggs. Individually caged females laid eggs at a rate >50% of their maximum daily oviposition on nights 3–5, and for females caged in groups of 50 males and 50 females this occurred on nights 4–10. Ovarian development also was consistently slower in the group-caged females than in the individually caged females, the former containing 16 to 93% as many mature eggs as the individually caged females, depending on age and prior exposure to plants. Male sexual maturation was not complete at adult emergence, and only 54% of day-l males were able to fertilize 4-d-old, virgin females. By night 4,98% of males were able to do so regardless of whether or not they were exposed to host plants. Females mated to day-4 males that were exposed to plants for the first three nights produced significantly more viable eggs compared with females mated to day-4 males that were not previously exposed to host plants.

Comparative Population Ecology of Eleven Species of Rodents in the Chihuahuan Desert

Comparisons of mark—recapture data on life histories and population dynamics of the 11 commonest species of nocturnal desert rodents inhabiting our experimental study site in the Chihuahuan Desert of extreme southeastern Arizona permitted assessment of the role of evolutionary relationships and ecological factors in the coexistence of these species. The species varied greatly in population density, extent of interannual variation in abundance, timing of reproduction, extent to which reproduction was seasonal, rate of disappearance of marked individuals, frequency and distance of lifetime dispersal movements, but perhaps less so in death rate and maximum longevity. Most of the species showed positively correlated year—to—year fluctuations in population density, suggesting that they responded similarly to interannual variation in precipitation, primary production, and availability of food resources. In contrast, there were both positive and negative correlations in seasonal patterns of reproductive activity and population density. Lifetime dispersal movements were inversely related to body size, suggesting that energy constraints cause the smallest species to move among rich patches in a coarse—grained manner. Patterns of similarities and differences among closely related (congeneric and confamilial) species suggested that evolutionary constraints sometimes, but not always, limited variation in life history and demography. The relationship between population ecology and competition among these species was not clear. We interpret the diversity of life histories and population dynamics in these coexisting species to be a consequence of: (a) a productive and spatially and temporally variable environment that provides a variety of resources that may be used in different ways, (b) historical biogeographic events that have made available a large regional pool of species from which potential colonists can be drawn, and (c) differences in population ecologies among the species that evolved primarily in other environmental contexts, but that permit coexistence by enabling the species to use different resources or to use the same resources in different ways.

Notes concerning Reproduction of the Montane Skink, Eumeces copei

Eumeces copei is a viviparous, high elevation Mexican lizard. Specimens examined were obtained from several locations within the Parque Nacional de Zoquiapan, Mexico, Mixico and from museum collections. This species mates in the fall. Males exhibit maximum testicular volume and activity during the fall. Likewise, females exhibit the onset of vitellogenesis in Sep- tember, ovulation during late fall and embryonic development throughout the remaining winter months with parturition occurring in late spring. This reproductive activity pattern appears com- mon in high elevation, viviparous reptiles and its adaptive significance is discussed. The genus Eumeces is a relatively large group of skinks primarily inhabiting the temperate regions of the Northern Hemi-

Reproductive seasonality of the nyala Tragelaphus angasi; The interaction of light, vegetation phenology, feeding style and reproductive physiology

AbstractIn Ndumu Game Reserve, South Africa, it was found that nyala males exhibited no seasonal sexual cycle. Although conceptions occurred throughout the year, there was a bimodal pattern of conceptions with the peaks in autumn and spring.After referring to other African bovids which also have bimodal patterns of reproductive activity, it was concluded that the cues for the two peaks are as yet unknown but must be provided by light or photoperiod. The factors which ultimately decide the amplitude of the peaks are vegetation phenology and feeding style of the animal. In nyala, peaks are masked by the occurrence of post‐partum oestrous cycles and a gestation period of approximately 7 months.

Effects of adult social experience of patterns of reproductive activity of socially deprived male rhesus monkeys (Macaca Mulatta).

Effects of adult social experience of patterns of reproductive activity of socially deprived male rhesus monkeys (Macaca Mulatta).