The zooplanktivorous flatworm Mesostoma ehrenbergii and the calanoid copepod Boeckella gracilis were observed to coexist in Patagonian fishless ponds. In laboratory experiments, we studied the vulnerability of B. gracilis to M. ehrenbergii predation, testing the attack rates on copulating pairs and single adults in different abundances. We also determined B. gracilis dimorphism, sex ratio and c...

Semen limitation (lack of semen to fertilize all of a female's eggs) imposes high fitness costs to female partners. Females should therefore avoid mating with semen-limited males. This can be achieved by using public information extracted from watching individual males' previous copulating activities. This adaptive preference should be flexible given that semen limitation is temporary. We first...

The gonochoristic soil nematode Caenorhabditis remanei strictly requires copulation for species propagation. Males of this species are sexually promiscuous with females of other species; therefore, we asked in this study whether virgin C. remanei females display evidence of mate choice. We digitally recorded and measured the locomotor behaviors of one or more virgin females in the presence of a...

Neural circuits that prevent a male C. elegans worm from copulating for several minutes after ejaculation have been identified.

The idea that copulation might increase predation risk is a classic suggestion, but empirical evidence to support it is surprisingly scarce. While some early work found decreased vulnerability to predation during mating, two lab and one very recent field study documented increased predation during mating in freshwater amphipods, water striders and locusts. Decreased vigilance, less efficient es...

Effects of four tropical plant (Aframomum melegueta, Zanthoxylum zanthoxyloides, Piper guineense and Eugenia aromatica) were investigated under tropical laboratory storage conditions for the protection of cowpea seeds against insect infestation. The plant materials were pulverised into fine powder after air drying and admixed with 20 g of cowpea seeds at the ...

Nuptial gifts are food items or inedible tokens that are transferred to females during courtship or copulation . Tokens are of no direct value to females, and it is unknown why females require such worthless gifts as a precondition of mating. One hypothesis is that token giving arose in species that gave nutritious gifts and males exploited female preferences for nutritional gifts by substituti...

Copulating males usually insert their penis into the female and ejaculate in her reproductive tract; but in some species, males are more invasive, puncturing the female body-wall and inseminating directly into her body-cavity. A spider has just been added to this list and new perspectives provided on why males harm females during copulation in the first place.