Mechanism, induction factors, and adaptive significance of dealation in the subterranean termite Reticulitermes speratus (Isoptera, Rhinotermitidae)

Abstract

We studied the dealation of a subterranean termite Reticulitermes speratus Kolbe from three different angles; mechanism, induction factors, and adaptive significance. During nuptial flight alates prevent the wings from breaking off by holding the wings in a 3-dimensional configuration. In the process of dealation, the alates hold the wings in a 2-dimensional configuration, half spread the wings in a lowered position, and bend the abdomen back toward the wings, thereby exerting high pressure at the basal sutures. This separates the wings from the body. The primary factor determining the timing of dealation appears to be isolation from other alates: It induces alates to shed their wings, whereas pairing has no effect on dealation in this species. Alates of termites are especially vulnerable to ant predation during the period between flight and colony foundation. An experiment designed to compare the risk of alates and dealates to predation by a termite-hunting ant, Brachyponera chinensis Emery, showed that dealation reduced the predation risk during the period spent running on the ground. and then compared the time required for the ants to kill the alates and dealates using the paired t-test.

Asexual queen succession in the subterranean termite Reticulitermes virginicus

“…As is typical of subterranean termites, colonies of both R. speratus and R. virginicus are founded by monogamous pairs of primary reproductives [1,19,20], but at some point, relatively early in the colony life cycle, the primary queen is replaced by her parthenogenetically produced neotenic daughters. These female neotenics then mate with either a primary or a secondary king to produce workers, soldier and alates through sexual reproduction.…”

Inbreeding and disease resistance in a social insect: effects of heterozygosity on immunocompetence in the termite Zootermopsis angusticollis

“…For example, Z. nevadensis alates appear to outbreed (Shellman-Reeve 2001) but secondary reproductives are common in Zootermopsis colonies that have lost one or both primaries (Castle 1934;Light & Illg 1945), probably reducing allelic variation in their offspring (Husseneder et al 1999;Thorne et al 1999;Vargo 2003;DeHeer & Vargo 2004). In addition, nesting ecology (Hamilton 1972), predation on alates (Lepage 1991;Matsuura & Nishida 2002) and disease risk (Rosengaus & Traniello 1993;Rosengaus et al 2000;Calleri et al 2005) may limit dispersal, which could also increase inbreeding (Roisin 1999). Cycles of inbreeding and outbreeding may have influenced the way in which termite colonies adapted to disease, outbreeding generating variation in disease resistance traits and inbreeding maintaining adapted disease-resistant genotypes selected for during colony growth (Thorne & Traniello 2003).…”

Disease and colony establishment in the dampwood termite Zootermopsis angusticollis: survival and fitness consequences of infection in primary reproductives

“…Colony foundation is a critical phase of termite life history that is composed of a series of events including dispersal-related predation (Lepage, 1991;Matsuura and Nishida, 2002), mate competition (Shellman-Reeve, 1999), nest site selection (Shellman-Reeve, 1994), mating (Rosengaus et al, 2000) and biparental care (Rosengaus and Traniello, 1991;Shellman-Reeve, 1990). In addition to these risks and costs, primary reproductives ('primaries') may be exposed to pathogens present on the body of mates or in the incipient nest chamber during pair formation and nest establishment (Rosengaus and Traniello, 1993;Rosengaus et al, 2000;Calleri et al, 2005).…”