I am currently planning a study on identifying the prey of a recently discovered Hydraena species in the Philippines using DNA-based methods. I have been looking for references on the diet of water beetles in general and on more specific taxa that Hydraena is a part, to no avail. Most studies I have found were descriptions of the morphology and habitat of water beetles. What could be the possible diet of a Hydraena species located in Southeast Asia?
This Hydraena is indeed strange. Have you tried looking at the stomach contents under a dissecting microscope or are specimens too rare? I am tempted to think they are scraping and eating algae and fungi, but maybe they are eating little worms.
I could spend hours just staring into those water ways in Metro Manila with all their small fish. Could the beetles be eating dead fish? You could see scales in the stomach contents.
Water beetles can be either herbivores, predators, or scavengers. Herbivorous beetles eat only aquatic vegetation, such as algae or leaves of hydrophytes. They also suck juices out the stem of a plant nearby. Scavenger beetles feed on decomposing organic material. The scavenged material can come from aquatic vegetation, feces, or other small organisms that have died. The great diving beetle, a predator, feeds on things like worms, tadpoles, and even sometimes small fish.
Possible diet: decomposing organic material, algae. Diet could be different in adult and larvae.
First step: observations in nature of places of beetle accomulations.
Second step: transfer in laboratory such "habitat" (ground, stones, gravel, palnts...) and observations in glass boxes, what kind of food is fodder or could be fodder (eating behavour).
Third: Experiments (probes to give different things or exclude somethings).
Fourth: dissecrions of stomach (can be not so effective, the beetles are too small and others causes).
Thank you for all your answers! I have actually found a reference from J.M. Glime's Bryophyte Ecology book that summarizes studies performed on many aquatic insects. Species such as Hydraena gracilis, H. minutissima and H. pygmaea have been observed to be correlated with moss substrates in Northern Spain. Other species such as H. rufipes, H. nigrita and H. pulchella have also been correlated with moss substares across Europe. I think that the species that I'm working, H. ateneo, was found in ponds with moss. I will double check but I suspect that H. ateneo feeds on moss as well.
Jayanth kumar sir do water beetles feed on tadpoles or on eggs of frogs. Please give more information about this if you have come across.
- Badges
- Science topic
- Similar topics
- Biological Science
- Zoology