Male decorated crickets (Gryllodes sigillatus) and katydids (bush crickets, family Tettigoniidae) provide a nuptial gift to females called a spermatophylax. As with many nuptial gifts, it’s something for females to eat during the process of sperm transfer; once the female has finished feeding on the spermatophylax, she detaches the sperm-transferring organ and consumes that too – putting an abrupt end to sperm transfer. The spermatophylax is a gift that is physiologically synthesized by the male
Far from being choosy about potential suitors, green-veined white butterfly (Pieris napi) females exhibit a complete lack of selectivity, even when it comes to mating with their relatives. This failure to discern siblings from non-siblings prior to doing the deed means that incest is a regular occurrence. Photo via Adobe Stock Both males and females show the same lack of inbreeding avoidance, which could result in substantial reproductive costs. Experimentally reared inbred larvae experience a
Our smallest primate relative, the female grey mouse lemur (Microcebus murinus) is extremely promiscuous during their short breeding season (just a few days out of the year). These ladies are of a similar morphological size to their male counterparts, and so they are not subject to intense intimidation or coercion from them. However, males are at their most abundant and eager during the female’s narrow window of ovulation, and up to fourteen males can actively
We’ve talked extensively about the importance of grandmothers. Do grandfathers contribute to their collective fitness in a parallel way to their female counterparts? So far all the data suggest that they do not. Photo via Adobe Stock This is due to the ever-important notion of paternity certainty for both fathers and grandfathers. A mother is 100 per cent certain that she is the parent of her offspring (yes, the memories of childbirth would be enough

November 3, 2021

Sperm Competition

Not all sperms are created equal. There is a great deal of variation in many aspects of sperm quality including morphology, mobility, and viability. As with all other aspects of biodiversity, there is tremendous selective pressure at the cellular level, especially with respect to the gametes. Males produce hundreds of millions of sperms, and so there is competition both within and between individuals as to which one will ultimately be the successful seed. Photo via

October 27, 2021

Milk-Stealing Sea Lions

In Stellar sea lions, misdirected care in the form of allonursing is common among first-time moms, whereas older, multiparous moms are very rough and unforgiving of unrelated juveniles that attempt to suckle from them. More experienced moms shove or throw unrelated pups that are attempting to nurse, often biting and significantly injuring them in the process. Photo via Adobe Stock The milk of Stellar sea lions is particularly high in fat due to the high

October 20, 2021

Maternal Grief In Primates

The continued carrying and care of deceased infants is a clear and well-established pattern of behaviour that occurs across many primate species. What is more difficult for us to understand are the emotional correlates of this behaviour. Photo via Adobe Stock When and how does a mother give up and finally abandon the body? Are there phases of grieving that must be addressed before such a thing can be done? Perhaps one of the largest

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