The objective of this study was to characterize the reproductive cycle of the chameleon goby, T. trigonocephalus. Gonadal development was investigated using a histological method. Specimens were collected monthly, from April 2009 to March 2010. The gonadosomatic index (GSI) of females began to increase in April, reaching the maximum in May, and declined sharply in August. In males, the GSI bega...

Patterns in nitrogen-fixing activity by Inga jinicuil Schl., a leguminous shade tree in Mexican coffee plantations, were monitored over a three-and-half year period using acetylene reduction. Year to year variation was unexpectedly large; mean annual fixation equalled 35 kg N ha yr, which constitutes a significant nitrogen input to the coffee ecosystem. Nitrogen-fixing activity occurred through...

The Eastern Box Turtle (Terrapene carolina carolina) is a widespread species that has recently experienced precipitous declines throughout its range. Although many studies have documented aspects of reproduction in box turtles, reproductive physiology of free-ranging animals is unknown and can be crucial in this species' recovery. Over a two-year period, we measured reproductive parameters, (vi...

To better understand the proximate causation of the two major types of mating seasons described for North American pitvipers, we conducted a field study of the cottonmouth (Agkistrodon piscivorus) in Georgia from September 2003 to May 2005 that included an extensive observational regime and collection of tissues for behavioral, anatomical, histological, and hormone analysis. Enzyme immunoassays...

The annual reproductive cycle of most seal species is characterized by a tight synchrony of births. Typically, timing of birth shows little inter-annual variation. Here, however we show that harbour seals Phoca vitulina from the Wadden Sea (southeast North Sea) have shortened their yearly cycle, moving parturition to earlier dates since the early 1970s. Between 1974 and 2009, the birth date of ...

prevalence of abortion is higher in women with autoimmune thyroid disease. in the majority of cases, however, no abnormality of thyroid function is detected despite the high levels of antithyroid antibodies. the direct influence of such harmful autoantibodies in female reproductive organs may serve a role in pregnancy loss. in this study, expression of thyroglobulin in the reproductive tissues ...

The southern banded guitarfish, Zapteryx xyster, and the Velez ray, Raja velezi, are two endemic elasmobranchs in eastern Tropical Pacific that commonly caught by bottom-trawl fishery. Reproductive cycles of these batoids were inferred from hepatosomatic gonadosomatic indexes (males females) oviductal gland width yolk follicle diameter (females) mature specimens collected along Costa Rica betwe...

The mating season of the Atlantic stingray (Dasyatis sabina), which begins in August and continues through April, is the longest documented for any elasmobranch fish. Despite this protracted mating period, female stingrays ovulate synchronously at the end of the mating season and there is no evidence for sperm storage by females. Thus, the proximate causal factors and ultimate function of this ...