A number of examples of parental care have evolved in the island of Jamaica and these form a fascinating puzzle for the attention of evolutionary biologists. After all, it is much safer for most parents to abandon their young as early as possible so that they can live to breed another day! And on the mainland this is what most of the "lower" animals do. But here we have crabs that "love" their children! And frogs! Not to mention the parrots which Sugar Belly says are just like humans! (He was especially impressed by the way in which a parrot can hold on with one foot while using the other foot to feed itself). In fact, parrots are collectively part of the "psittacines" group where eggs have large yolks and parental care is extensive. Parrots form long-lasting pair bonds and it is a regular thing at Windsor to see family groups consisting of two adults and last year's offspring. At least until the breeding season gets under way, but even then the youngsters hang around.
But, back to crabs and frogs.
Jamaican endemic frogs exhibit some amount of parental care. All the Eleutherodactyls have direct development from heavily-yolked egg to froglet (bypassing the tadpole stage, presumably as an adaptation to lack of permanent surface water) and six of seven Jamaican species show parental attendance of their eggs. But Eleutherodactylus cundalli (which breed in the Windsor Great Cave, where the humidity is 100%) guard their clutch until the young hatch as tiny froglets and then climb onto the back of the mother who carries them out of the cave (see photo). (See Rudi Diesel 1995)
Jamaica's hylid frogs breed in the water-filled leaf-axils have adapted to the harsh environments of bromeliads (i.e., low oxygen levels and limited food reserves) by producing rapidly developing eggs and by laying further eggs which are eaten by the first-born larvae. Remarkably, the eggs laid for the first few days are fertilised (presumably this means they are a "back-up" in case the first clutch fails. But fertilised eggs also "keep" longer); later on, the eggs are laid unfertilised, presumably because they larvae now consume them rapidly enough that "shelf life" is not an issue. (See Rebecca "Frog Lady" Thompson who carried out this research at Windsor in 1996).
The "snail crabs" are another, remarkable example of "brood
care" in the Cockpit Country and raise their families in the shells
of dead snails. They actually turn the shell over to put the
aperture downwards so that rain does not flood their "house". They
then carry dew water so that the larvae (which still have gills)
can survive. (Photo).
Another example of brood care is the bromeliad crab (Metopaulias depressus) which raises its young in the water-filled bromeliads. The mother manipulates water quality by removing detritus , circulating water to oxygenate it and carrying empty snail shells into the bromeliad as both a calcium source and a pH buffer (Schubert et al, Nature vol 393, 28May,98) We value your feedback and comments: