Phylogeny and Classification

The Trichoptera and its sister group Lepidoptera are thought to have evolved from a stem group of mecopteralike insects in the Permian. A few Trichoptera have been collected from Lower Permian deposits in the Czech Republic and the United States, and representatives of some extant families probably existed at least as early as the Jurassic. Fossilized caddis larval cases are known from the Lower Cretaceous, by which time the order had undergone a wide radiation. Within the order the evolutionary development of the larval stage has far outstripped that of the adult. Ross (1956, 1967) suggested that the order evolved in a forested habitat, through which ran small, cool-water streams. Such a habitat would not be conducive to a wide adaptive radiation of adults, but larvae, evolving in a new, relatively unexploited habitat, were able to diversify in a remarkable manner. Subsequently, representatives of many families have invaded warm, moving-water, many still-water, and even some temporary aquatic habitats (Wiggins, 1996). Curiously, perhaps, despite their wide-ranging differences in behavior and ecology, caddis larvae are quite uniform morphologically, making their identification sometimes quite difficult. By contrast, the evolution of adults has been concerned for the most part with the development of specific behavior patterns and changes in the genitalia to prevent interspecific mating, the latter making species-level identification relatively easy.

Trichopterists are agreed that the traditional arrangement whereby the extant Trichoptera were placed in two suborders, Annulipalpia and Integripalpia, is no longer tenable. Unfortunately, they have not yet reached a consensus on a more appropriate classification (see Kjer et al., 2002). The central problem is the position of the Rhyacophiloidea, with some

FIGURE 9.21. A suggested phylogeny of Trichoptera.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

Get My Free Ebook


Post a comment