成虫取食对棉铃虫雌蛾繁殖的影响

试验对雌蛾设置５个食物处理,定量地研究了成虫取食对棉铃虫蛾繁殖和寿命的影响,成虫取食对雌蛾与寿命和主效量均显著影响,补充营养延长雌蛾寿命,提高产卵量,并且」补充营养对产卵量的影响比其对寿命的影响更大,分析表明被营养的作用在于提高雌蛾后期的存活率和产卵量,前期补充营养比后期补充营养具有更大的作用。雌雌全重及其蝮部干重受成廊和的自龄的双重影响,补充营养时雌蛾体重、腹部干重及其脂肪含量下降慢,补充营养可     

Assessing reproductive potential and gestation in nurse sharks (Ginglymostoma cirratum) using ultrasonography and endoscopy: An example of bridging the gap between field research and captive studies

Over a period of 3 years, five reproductively active female nurse sharks (Ginglymostoma cirratum) from a wild, actively mating population of nurse sharks were captured, confined, and periodically examined through the course of gestation to determine the gestation period and characterize paternity. In the final year of the study, candidate animals were first evaluated in the field by ultrasonography, and the selected animals were then transported from the study site to holding facilities at SeaWorld Adventure Parks in Orlando, Florida. Periodic monitoring of the animals was conducted by ultrasonography, endoscopy, and routine blood analysis. Gestation was determined to be a minimum of 131 days, multiple paternity was shown for two individual litters, and ultrasonography and endoscopy were shown to be useful adjuncts for assessing pregnancy and monitoring gestation in this species. Poor survival of offspring, and small litter size may be a consequence of handling and transporting the animals, and the use of invasive procedures such as endoscopy. Zoo Biol 22:179–187, 2003. © 2003 Wiley‐Liss, Inc.     

Evolutionary aspects of gonadotropin-releasing hormone and its receptor

Summary 1. Gonadotropin-releasing hormone (GnRH) was originally isolated as a hypothalamic peptide hormone that regulates the reproductive system by stimulating the release of gonadotropins from the anterior pituitary. However, during evolution the peptide was subject to gene duplication and structural changes, and multiple molecular forms have evolved.2. Eight variants of GnRH are known, and at least two different forms are expressed in species from all vertebrate classes: chicken GnRH II and a second, unique, GnRH isoform.3. The peptide has been recruited during evolution for diverse regulatory functions: as a neurotransmitter in the central and sympathetic nervous systems, as a paracrine regulator in the gonads and placenta, and as an autocrine regulator in tumor cells.4. Evidence suggests that in most species the early-evolved and highly conserved chicken GnRH II has a neurotransmitter function, while the second form, which varies across classes, has a physiologic role in regulating gonadotropin release.5. We review here evolutionary aspects of the family of GnRH peptides and their receptors.     

Assuming reproduction to be a function of consumption raises doubts about some popular predator–prey models

1. Predator−prey models that abide by the conversion rule (reproduction rate of predators is a function of the consumption rate) are more plausible.
2. Although the conversion rule is quite general, many predator−prey models in current ecological literature fail to coordinate the arguments of the functional and numerical responses.     

OLA-DRB1 microsatellite variants are associated with ovine growth and reproduction traits

The DRB1 intron 2 (GT)_n (GA)_m microsatellite was genotyped in experimental flocks of seven Merinoland rams and 249 ewes as well as their offspring (381 lambs) from consecutive lambings. A total of 16 DRB1 alleles were detected, ranging between 353 and 857 bp. In comparison with carriers of other alleles, the ewes carrying the predominant 411 bp allele had higher values of all the recorded fertility traits. For ewes carrying the 394 and 857 bp alleles, the birth weight of lambs was about 400 g higher as compared to the residual group of ewes. The observed associations could be due to differences in disease resistance, cell recognition or tissue differentiation between carriers of various MHC haplotypes which can in turn affect individual fertility and growth performance.     

Reproduction of macrourids in the upper slope of the north-western Ionian Sea

Aspects of reproduction of macrourid fish in the north-western Ionian Sea are reported. Data were collected during 12 trawl surveys carried out between 1993 and 1995. Mature and running ripe females of Coelorhynchus coelorhynchus, Hymenocephalus italiens and Nezumia sclerorhynchus were found all year round. Mature females of Trachyrhynchus trachyrhynchus were found mainly in August.