The sparing effect of dose-fractionation in adultDrosophila

Summary The sparing effect of dose-fractionation was observed in adult male and femaleDrosophila melanogaster; 24-, 48-, 72-, and 96-h-old female flies, in general, show a higher recovery (increase in life-span) following dose-fractionation as compared to the males of the respective age. Recovery in 72-h-old females is maximal (31% increase in life-span) as against only 12% increase in the life span of the males.     

The identification of spiroacetals in the volatile secretions of two species of fruit fly (Dacus dorsalis,Dacus curcurbitae)

Summary Aeration extracts from femaleDacus cucurbitae and femaleDacus dorsalis have been shown to contain a variety of 2,8-dialkyl-1, 7-diaxospiro [5.5] undecanes together with N-3-methylbutylacetamide.     

Chromosomal investigation ofCtenopharyngodon idella x Aristichthys nobilis hybrids

Summary Diploid, triploid, and gynogenetic offspring resulted from hybridizing femaleCtenopharyngodon idella with maleAristichthys nobilis.This research was supported in part by a contract with the Coachella Valley Water District, Coachella, California.     

Studies on the thyroid in transgenic mice expressing the genes for human and bovine growth hormone

Summary The thyroid glands of transgenic mice (TM) expressing the genes for human (h) and bovine (b) growth hormone (GH) were studied. The percentages of larger follicles inhGH TM of either sex were significantly greater than in the corresponding normal littermates, and follicles ranging up to 350 m in diameter were present in malehGH TM. In contrast, thyroid follicles were only slightly enlarged in malebGH TM, and were unchanged in femalebGH TM. The serum concentrations of T4 were significantly decreased in malebGH TM and not altered in the other groups. Serum concentrations of T3 were slightly, but significantly increased in femalehGH TM and femalebGH TM, but were unaffected in male TM of either type. Since the principal difference between these foreign GHs in rodents is the additional lactogenic activity of human GH, these results may indicate that the effects of prolactin can influence the development of the thyroid.     

A reappraisal of the hormonal regulation of larval fat body histolysis in femaleDrosophila melanogaster

The histolysis of larval fat body cells in adult femaleDrosophila melanogaster was examined in wild type and mutant animals. The fat body cells of wild type (Canton-S),apterous ^56f homozygotes,apterous ^78jts homozygotes and heterozygotes,apterous ⁴/+, ecdysoneless¹ homozygotes and heterozygotes all underwent histolysis normally during the 72 h following adult eclosion. Only in the case ofap ⁴/ap⁴ adults did the cells fail to histolyze normally. The fat body cells of both diapausing and non-diapausing wild type females underwent histolysis at the same rate. Attempts to demonstrate histolysis in vitro were unsuccessful, even in the presence of juvenile hormones (JHs), larval ring glands, or adult ovaries. In all strains other than theap ⁴ homozygotes, a significant proportion of larval fat body cells were dead at any time while theap ⁴/ap⁴ animals, almost all cells remained viable. It is postulated that fat body cell lysis following eclosion is not a JH-mediated event, but is elicited by an as yet unidentified factor(s), possibly originating in the ovary.     

Mate choice and male competition inOrchesella cincta (Collembola)

Summary Both male and femaleOrchesella cincta (Collembola) were able to discriminate between spermatophores of different origin. Females chose spermatophores deposited by closely related males while males preferentially destroyed spermatophores of other males.     

Mating patterns of virgin and inseminatedDrosophila melanogaster of different alcohol dehydrogenase (Adh) genotypes

Summary Female choice mating experiments showed virgin femaleD. melanogaster of the 3Adh genotypes chose heterozygous (Adh ^F /Adh ^S ) males most commonly. Inseminated females chose mates randomly, but the likelihood of a female remating was genotypically dependent.Acknowledgment. Financial support was provided by the Australian Research Grants Commitee.     

Histopathological effect of thiourea on the ovarian tissues ofSarcophaga ruficornis (Fabr.)

Summary The primary target of thiourea in femaleSarcophaga are the follicles in the ovarioles. The follicle cells as a result become syncytial and their nuclei get pycnotic, inhibiting the transport of nutrient material into the nurse cells and of yolk into the oocytes. The subnormal eggs produced are not viable.     

Precocene treatment of the female tsetse flyGlossina morsitans morsitans sterilises her female offspring

Summary When adult femaleGlossina morsitans morsitans were treated with either precocene I or precocene II, females of the F₁ generation, emerging from pupae of the 2nd, 3rd and 4th reproductive cycles failed to develop oocytes.Acknowledgments. The authors wish to thank Dr G. C. Unnithan for helpful discussions.     

Ultrasonic vocalizations by adult prairie voles,Microtus ochrogaster

Summary Male and femaleMicrotus ochrogaster were presented with anesthetized and awake conspecifics while ultrasonic vocalizations (USVs) were monitored. Males produced significantly more USVs than females during 5-min testing sessions. Males tended to produce more USVs to unfamiliar females than to familiar female siblings. Sexual experience led to increased USV scores by males. These results suggest that USVs by male prairie voles communicate to females the male's gender and his availability for reproductive behavior.     

A new cell line (XTY) from a tumor ofXenopus laevis

A new cell line (XTY) was derived from a tumor of a femaleXenopus laevis. This cell line has been proliferating in standard amphibian culture medium for more than 4 years (470 generations) and has a doubling time of 75.5 h at 25°C. The cells aggregate into large groups, and their stellate morphology and the expression of desmin demonstrated by immunocytochemistry suggest that their origin is not epithelial.     

Sexual dimorphism in the defensive secretion of a carabid beetle

Summary The defensive secretions of male and femaleOodes americanus display striking qualitative differences. Altogether 13 carboxylic acids were identified in the secretions of the two sexes. Methacrylic, crotonic, and tiglic acids are produced exclusively by the female; the male lacks these unsaturated components, but produces their saturated analogs. 2-Methylbutyric acid is a major component produced by both sexes. Shared components also include hexanoic, (E)-2-hexenoic, benzoic, and (E)-2-octenoic acid, of which the latter two had not previously been reported from carabid beetles.Paper no. 98 in the series Defense Mechanisms of Arthropods; no. 97 is by Smedley et al., J. Lepid. Soc., in press.     

Recombination frequency and DNA content of the distal part of the second chromosome ofDrosophila hydei sturtevant

Summary Four visible markers, including a newly isolated one, have been cytologically mapped on the second chromosome ofDrosophila hydei. Both the frequency of recombination and the amount of DNA between these markers have been determined. From these data the coefficient of exchange has been calculated.     

Effect of intercalating mutagens on crossing-over inDrosophila melanogaster females

Summary In order to evaluate the effect of several intercalating compounds on crossing-over inDrosophila melanogaster females, acridine orange, acriflavine, chloroquine, ethidium bromide and quinacrine were fed separately to larvae ofy ct f/+++ genotype. Our results show that acridine orange, acriflavine and ethidium bromide increase significantly the recombination frequency at thect-f region and support the view that, for intercalating agents, there is a relationship between clastogenic activity and female recombination induction.     

Genetic load and effective size of natural populations ofDrosophila melanogaster in Korea

Summary The effect of 750 second chromosomes ofDrosophila melanogaster on viability was studied. 19.3% of them proved letal or semilethal (=drastics) in homozygous condition. Compared to data obtained in previous years at the same sampling site, a significant frequency decrease of drastics during the past decade could be observed. The dynamic processes taking place in the Korean wild populations ofD. melanogaster are discussed.Acknowledgment. This work was supported by a research grant from the Korean Science and Engineering Foundation.     

Identification of JH III as the princpal juvenile hormone inLocusta migratoria

Summary JH titers in the hemolymph of nymphal and adult femaleLocusta migratoria migratorioides (R. and F.) were determined using a selective mass spectrosc opic detection technique. Only JH III could be found in either stage, with no detectable JH I (or II). Titers observed were 10–1000-fold lower than those found via a recently reported radioimmunoassay procedure.     

Genetic variation in natural populations: Morphological traits inDrosophila melanogaster

Summary In a wild population ofDrosophila melanogaster located near Madrid (Spain), it has been found that the frequency of morphological mutant phenotypes is 0.36 per captured female. The study of these females shows that they carry 3.6 recessive mutants in heterozygous condition per female. The genetic variability found is higher than the frequencies observed by other authors in other natural populations.I thank Dr F.J. Ayala for useful discussions and help in preparing the English text.     

Laboratory and field studies of the female sex pheromone of the olive moth,Prays oleae

Summary Analysis by GC-EAG indicates that abdominal tip extracts of femalePrays oleae contain a tetradecenal. Synthetic (Z)-7-tetradecenal elicits a strong EAG respones from maleP. oleae and field tests it to be comparable in attractancy with the virgin female moth. (Z)-9-Tetradecenal also produces a strong EAG response but it is not an attractant and, when added to (Z)-7-tetradecenal, markedly reduces trap catches.Acknowledgments. The authors are indebted to Mr N. Psylakis, Agricultural Research Centre, Chania, Crete, and to Dr D. Vassilopoulos, Benaki Phytopathological Institute, for providing facilities for this work. They thank the Commonwealth Institute of Entomology, London, for moth species confirmation.     

Accumulation of drastic mutants in selection lines for resistance to the insecticides dichlorvos and malathion inDrosophila melanogaster

Summary Viability tests were performed on second and third chromosomes from lines ofDrosophila melanogaster selected for increased resistance to the organophosphorus insecticides dichlorvos and malathion, in order to evaluate the accumulation of drastic alleles. Our results show that malathion reduces significantly the relative viability of chromosome 3 and also increases the frequency of drastic alleles in this chromosome, while dichlorvos increases significnatly the frequency of drastic alleles in chromosome 2.Work supported in part by the Spanish Ministry of Education and Science (Grant No. 0577/84 CAICYT).—We are grateful to Productos Cruz Verde S.A. and Agrocrós S.A. for generously supplying the insecticides dichlorvos and malathion, respectively.     

Regulation of feeding and ovipositional success ofAmblyomma americanum ticks

Summary Duration of the adult femaleAmblyomma americanum feeding period was found to be dependent upon male receptiveness to mating, which was in turn dependent upon when males were placed with females. Prolonging the time to mating by 5 days had no effect on female engorgement weight or length of the preovipositional period, but prolonging mating by 10 days substantially decreased the number of ovipositing females and ablated egg viability. In the absence of males, females were severely stunted in size and had to be forcibly removed from the host.Supported in part by grants from the United States Public Health Service, National Institutes of Health No. AI 17555, RR 05443, and from the Rockefeller Foundation.