There are many more species of fish (about 28,000 species) than of any other kind of vertebrate (amphibians, reptiles, birds and mammals). And there are about 30,000 species of orchid, in a single taxonomic family. But those seemingly impressive numbers fade into the background in comparison to beetles.<\/p>\n
Numbering well over 350,000 (and counting), there’s a species of beetle for every ecological job — predators and parasites, herbivores and detritivores, scavengers and pollinators. They range in size from a giant six or eight inches long down to a wee thing only a fraction of a millimeter in length. Beetles have been around for a long time. Their fossil history begins before that of bees and ants, and long before that of butterflies. Beetles appeared at least 230 million years ago, already diversified in their ecologies. Their diversity got a boost from the appearance of conifers, and then again from the arrival of the flowering plants, as they began to exploit these new resources. In fact, they were probably the first insects to pollinate the early flowering plants, since there were no bees or butterflies yet.<\/p>\n
[Diversity in nature: Winter brings a variety of observations]<\/a><\/ins><\/p>\n The phenomenal diversity of beetles is impossible to capture in a short essay. So let’s reduce the problem (slightly) by considering selected taxonomic families: the weevils or snout beetles (Curculionidae) and the rove beetles (Staphylinidae). These two families are probably the largest, in terms of the numbers of species. And I can’t altogether leave out three other interesting, large families.<\/p>\n Consider first the weevils, with over 80,000 species, according to some taxonomists. Most weevils feed on the flowers and leaves of flowering plants (which now number hundreds of thousands of species). With that long snout, they bite and chew the plant tissues. The most notorious species is perhaps the boll weevil, which feeds on flower buds and fruit of cotton and ravaged U.S. cotton crops in the 1900s. A few weevils are aquatic, including some that feed on native and introduced water milfoil. One acts like a dung beetle, collecting the dung of Australian wallabies for raising their larvae.<\/p>\n [Birds, shrews transform in hibernation]<\/a><\/ins><\/p>\n One branch of the weevil family includes the bark and ambrosia beetles, which can wreak havoc in conifer forests. There’s a variety of ambrosia beetles, whose adults and larvae feed on ambrosia fungi that grow on wood. Some of these beetles even carry bits of the fungus in special pockets, and so they inoculate new tunnels under the tree bark.<\/p>\n The rove beetles number at least 60,000 species, with vast numbers still uncatalogued by taxonomists. Most of them are small and inconspicuous, often living in leaf litter, under loose bark, in caves, and other places that are usually beneath our notice, scavenging whatever they can find. Some feed on carrion, a few are external parasites on fly larvae, some feed on fungal spores, and some burrow in shoreline sand to feed on algae and diatoms. Here in Southeast, one species of rove beetle is the chief pollinator of western skunk cabbage.<\/p>\n