Feeding ecology and life-history strategy of nesting males in a fish with long parental care, Lusitanian toadfish (Halobatrachus didactylus, Batrachoididae)

The Lusitanian toadfish, Halobatrachus didactylus, like other batrachoidids, is a benthic fish species with nesting behaviour during the breeding season. During this prolonged period it engages in mating activities and remains in the nest providing parental care. It is not known whether males feed while providing parental care but it is likely that their limited mobility may restrict their diet and influence their fitness. As a consequence, egg cannibalism could occur as a life-history strategy. The aim of the present study is to ascertain the feeding behaviour of nesting males, in comparison to mature non-nesting males, and to identify potential life-history traits related to egg cannibalism. Nest-holders were sampled from artificial nests placed in an intertidal area of the Tagus estuary, only exposed during spring low tides. The diet of nest-holders was compared with that of non-nesting mature males from the same area, captured by otter trawl. The present study demonstrates that despite their constrained mobility nest-holders feed during the breeding season, although in a more opportunistic fashion than non-nesting males. Nest-holders showed a generalist feeding behaviour, with a more heterogeneous diet. Egg cannibalism was not related to male condition, paternity or brood size but showed a higher incidence early in the season when water temperatures were lower. The results suggest a possible seasonal trade-off strategy between care and energy recovery, triggered by environmental factors, where under unfavourable conditions to sustain viable eggs the male may recover energy by eating eggs, thus benefiting future reproductive success, later in the season.

Measuring sperm backflow following female orgasm: a new method

Background: Human female orgasm is a vexed question in the field while there is credible evidence of cryptic female choice that has many hallmarks of orgasm in other species. Our initial goal was to produce a proof of concept for allowing females to study an aspect of infertility in a home setting, specifically by aligning the study of human infertility and increased fertility with the study of other mammalian fertility. In the latter case - the realm of oxytocin-mediated sperm retention mechanisms seems to be at work in terms of ultimate function (differential sperm retention) while the proximate function (rapid transport or cervical tenting) remains unresolved. Method: A repeated measures design using an easily taught technique in a natural setting was used. Participants were a small (n=6), non-representative sample of females. The introduction of a sperm-simulant combined with an orgasm-producing technique using a vibrator/home massager and other easily supplied materials. Results: The sperm flowback (simulated) was measured using a technique that can be used in a home setting. There was a significant difference in simulant retention between the orgasm (M=4.08, SD=0.17) and non-orgasm (M=3.30, SD=0.22) conditions; t (5)=7.02, p=0.001. Cohen’s d=3.97, effect size r=0.89. This indicates a medium to small effect size. Conclusions: This method could allow females to test an aspect of sexual response that has been linked to lowered fertility in a home setting with minimal training. It needs to be replicated with a larger sample size.

Mating system variation among populations, individuals and within and among fruits in Bertholletia excelsa.

The aim of this study was to investigate variation in mating system among three Brazilian Amazon populations of the tree Bertholletia excelsa with different levels of anthropogenic interventions. We collected open-pollinated seeds from one natural population, remnant trees dispersed in a pasture, and trees from a plantation. Outcrossing rate not varied among the populations and indicates that all seeds were originated from outcrossing (tm=1.0). Mating among relatives was significant higher in the plantation than forest and pasture populations, probably due the fact that many trees are related in the plantation. Correlated mating was significantly higher in pasture (rp=0.47) and plantation (rp=0.51) than in the natural population (rp=0.22), suggesting that trees in natural population are pollinated by a higher number of pollen donors. The paternity correlation was significantly higher within (rp(w)=0.41) than among fruits (rp(a)=0.18), showing a higher probability to find full-sibs within than among fruits. The fixation index was generally lower in seed trees than in their seedlings, suggesting selection for heterozygous individuals from seedling to adult stages. Progeny arrays collected from the natural population had a lower proportion of pairwise full-sibs than in pasture and plantation and higher variance effective size (2.75) than trees in pasture (2.15) and plantations (2.22). Results highlight that seed collections for conservation, breeding and reforestation programs preferentially should be carried out in natural populations due low proportion highest variance effective size within progeny.