Environmental variation can wreak havoc on animals that use auditory signals to find mates. Ever tried to carry on a conversation with a potential mate in a noisy nightclub? Have you had much success in legitimate communication with deafening music and background chatter? I didn’t think so. Imagine the struggles faced by animals that depend on communication via mating vocalizations against noisy backdrops. Even the most basic environmental perturbations can have profound effects on the
Externally fertilizing fish provide several fascinating examples of cryptic female choice at work. In these systems, females lay their eggs in nests on the floor of their aquatic habitat, and males fertilize them externally. Congeneric (two separate species belonging to the same genus) Atlantic salmon and Atlantic trout (Salmo salar and S. trutta respectively) have overlapping habitats throughout most of their natural ranges. Photo via Adobe Stock These two fish species can successfully interbreed, although
In some of the more simplistic cases of cryptic female choice, females prove unable to discern a good mate from a bad one during pre-coital activities. In many insects it’s extremely difficult to tell a male from a female, much less distinguish between a high-quality male partner and a low-quality one. There isn’t a whole lot of “getting to know you” time prior to the copulatory event. In the insect world there are no long
The parenting hypothesis posits that first-time moms (moms who haven’t given birth) will allonurse unrelated offspring as a means by which to gain experience and skill for when the “real thing” occurs. Photo via Adobe Stock This kind of behaviour is observed in many primate species, such as Japanese macaques, in which both related and unrelated females will suckle newborns. If a female is pregnant for the first time and she’s in her last few
The fire salamander Salamandra salamandra is an organism with a perplexing level of parental plasticity. Females are generally oviviparous (not to be confused with oviparous), which means that somewhere between thirty and sixty larvae are produced and birthed at a developmental stage prior to metaphophosis (the transition from aquatic, free-swimming larvae to terrestrial adults). The only food source for these offspring is their yolk sac. However, females are also capable of an alternative developmental mode:
Close bonds form between females who see each other all the time, although in the case of alloparenting and shared nursing between house mice, there is little or no genetic relatedness between females. Group living mammals and other species who reproduce communally or share a common roosting ground have the potential to become both friendly and trusting of the individuals in their immediate vicinity. When mothers give birth at a similar time and find themselves
If the scene for heterospecific copulation was that of a horror film, the scene for hybridization is more like that of science fiction. In nature when we see successful hybridization, this means that species are so closely related that copulation, fertilization, and gestation have all been successfully achieved. While this is certainly eerie and a subject of curiosity and intrigue, chances are that this high level of sexual success doesn’t involve the genital mutilation or