History Archaeology. Help Community portal Recent changes Upload file. A low incubation temperature during the development of this lizard's egg reverses some genotypic females XX into "phenotypic" males—so that they have only functioning male reproductive organs.
Marine Biology. This segment presents data documenting the protection of sea urchin embryos by mycosporine amino acids. While no single cause for these declines has been identified and the extinctions may be due to the convergence of more than one causethe fact that they have occurred in undisturbed areas and throughout the world has prompted considerations of global phenomena see Phillips Reefkeeping Magazine.
Their results suggest that estrogens are important in the regulation of spermatogenesis in this protogynous hermaphrodite. Weismann noted that butterflies that hatched during different seasons were colored differently, and that this season-dependent coloration could be mimicked by incubating larvae at different temperatures.
The worm will cover the prey with toxic slime from its proboscis, paralyzing the crab so the ribbon worm can slide into a crack in the shell and eat the crab from the inside out. One such study was performed by Kobayashi et al. Selection for protogyny may occur where there are traits in the population that depress male fecundity at early ages territoriality, mate selection or inexperience and when female fecundity is decreased with age, the latter seems to be rare in the field.
At the Smithsonian Visit. The Quarterly Review of Biology.
Tinsley M. Thermally induced genital appendages on mosquitoes. Cytogenet Genome Res — High-prevalence male-killing Wolbachia in the butterfly Acraea encedana. This correlation is seen to hold under natural conditions as well.
Transfer of a parasitic sex factor to the nuclear genome of the host: A hypothesis on the evolution of sex-determining mechanisms in the terrestrial Isopod Armadillidium vulgare Latr. These include an immunity-related gene in rainbow trout Oncorhynchus mykiss  and Sxl in Drosophila whose ortholog has a non-sex-related function in mRNA splicing in other flies .
Protection of the egg by sunscreens and repair enzymes The survival of embryos in their environments poses major problems. In numerous instances, environmental cues are a fundamental part of the organism's life cycle. A Caterpillars that hatch in the spring eat oak catkins and develop a cuticle that resembles these flowers.