Impacts of Non-Lethal High-Temperature Stress on the Development and Reproductive Organs of Bradysia odoriphaga

Bradysia odoriphaga is an agricultural pest in China’s vegetable industry. In this study, pupae and adults were exposed to various non-lethal high-temperatures. The results demonstrated a decreased rate of eclosion once the pupae were exposed to temperatures exceeding 37 °C for 1 h. No effect on the lifespan of unmated female adults was observed after exposure to temperature stress, while unmated male adult lifespan decreased (>37 °C for 2 h). The size of the testis and ovaries for unmated male and female adults decreased, as did the fecundity and egg hatching rate for mated females. Compared with the control group (25 °C), the testis size of unmated male adults decreased after high-temperature stress followed by recovery at 25 °C for 1 h, though the size of the ovaries of female adults did not change. Additionally, the size of the testis and ovaries for unmated male and female adults decreased following high-temperature stress and 24 h of recovery at 25 °C. High temperatures affected males more than females; 37 °C is the critical temperature to control the population of B. odoriphaga. These results lay the foundation for the future development of environmentally friendly high-temperature prevention and pest-control strategies.

Evolutionary significance of promiscuity in an aphidophagous ladybird,Propylea dissecta(Coleoptera: Coccinellidae)

The short- and long-term consequences of monogamy and promiscuity in an aphidophagous ladybird,Propylea dissecta(Mulsant) in terms of reproductive performance and offspring fitness were investigated. Promiscuous females were more fecund and laid more viable eggs than monogamous ones. Amongst promiscuous females, those mated with multiple males (freedom for mate choice) had significantly higher reproductive output than those mated daily with a new unmated male. The increased reproductive output of females mated with an unmated male each day in comparison to monogamous ones might possibly be a result of their increased ejaculate size. The further increase in reproductive output, when a female was allowed to choose a mate, may be because of repeated preferential mating with the fitter males. Results on long-term consequences of promiscuity revealed faster development and increased survival in offspring of promiscuous females at 25, 27 and 30%C. The percent adult emergence was more strongly influenced than development by the mating regime. There were no statistically significant differences in survival of offspring of promiscuous females (mate choice) at the three temperatures, while the percent survival of offspring of monogamous females differed significantly. Offspring of promiscuous females (mate choice) were fittest in terms of development and survival, which indicates their probable better genetic constitution and subsequently that of chosen mates. Thus, promiscuity has both short- and long-term benefits and is advantageous to ladybirds. The presence of long-term benefits in terms of fitter offspring probably indicates the evolutionary rationale behind the prevalence of promiscuity in ladybirds.

A SIMPLE TECHNIQUE FOR INDEXING THE MATING STATUS OF MALE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

Section 7 of the primary simplex of the ductus ejaculatorius of unmated male spruce bud worm moths, Choristoneura fumiferana, contains a yellow substance that is not present in recently mated males. The yellow substance occurs in laboratory-colony males reared on diet and in feral males reared on foliage. It is shown that the presence/absence of this material is a reliable index of copulation during the previous 24 h. Although the yellow substance regenerates over a period of several days, males 0–72 h post-copulation may be indexed when compared with unmated males of similar age.

An Experimental Analysis of the Use of Location Calls By Japanese Quail, Coturnix Coturnix Japonica

Three experiments were undertaken to study location calls used by Japanese quail. The first experiment was carried out to examine differences in emission of structurally similar locaton calls by Japanese quail, Coturnix coturnix japonica, in different contexts. Such comparisons may reveal the possible course of evolution of one call from another. Comparison between the unmated male Japanese quail's crow and the mated male's separation crow indicates the following similarities and differences: a. The same physical unit, the three part crow, is being used in both instances. The same inter-individual differences between crows of unmated males are also found between their separation crows. b. A staccato call normally accompanies separation crowing whereas this is not the case in crowing of unmated males. The individual notes of the staccato call closely resemble those emitted by the male while tidbitting. c. The crow emitted by unmated males is louder and less variable in intensity than is the separation crow. d. Separation crows occur in temporal groups or bouts whereas the crows of the unmated male usually occur individually. Initial crows within a bout are relatively faint. The second experiment was undertaken to study the function of the separation crow, the staccato call, and the cricket call. In this experiment, pairs of quail were successively housed in a series of interconnected compartments. Separation and contact maintenance were controlled by the animals own movements. The calls emitted by the animals were tape recorded and their positions were recorded every 5 seconds. Three lines of evidence for the three calls serving as location calls were examined: 1. The call is emitted primarily when visual contact between animals is attenuated or absent. 2. The call is answered with another call that is a known location call. 3. The call causes locomotor behavior in the receiver that results in contact maintenance or establishment. The data show that the cricket and separation crow serve as location calls and provide evidence for the staccato call serving as a location call as well. The effect of increased ambient noise level upon the emission of the separation crow when separation is due to movements of the male and female was also assessed. Significantly more separation crows and instances of separation crowing occurred during the high ambient noise level condition. Analysis of the positional data indicate that the differences are not due to differences in visual contact. The effect of ambient noise level on separation crowing was explained in terms of 2 factors: a. A direct stimulatory effect upon the male perhaps due to masking of the fainter staccato call as well as the separation crows emitted by the male. Previous work by the author supports this conclusion. b. An indirect effect upon the male caused by masking of noises and vocalizations emitted by the female. Data from a third experiment in which male separation crowing was measured under conditions of visual and visual and acoustical isolation from the female support this conclusion.