Comparative studies on alate wing formation in two related species of rotten-wood termites: Hodotermopsis sjostedti and Zootermopsis nevadensis (Isoptera, Termopsidae)

Abstract

Termite colonies are comprised of several types of castes that differentiate throughout postembryonic development. In termopsid termites (family Termopsidae), alates are normally differentiated from apterous instars by two nymphal instar stages and three moulting events. Here, we report that of the rotten-wood termite Hodotermopsis sjostedti. There is only a single nymphal instar between the pseudergate and alate stages. During the annual alate production season in June/July, we observed some nymphs with small wing buds which were dorsally swollen. Those nymphal individuals subsequently moulted into alates through only a single moult. We examined their histology and internal morphology and observed that the folding pattern of the newly formed wings was very different from that seen in second stage nymphs of the closely related species Zootermopsis nevadensis. The newly formed wings of H. sjostedti are formed inside the relatively smaller wing buds and therefore must be folded in a complicated manner. Our observations revealed that the tips of the folded wings were elongated and bent, such that they overlapped in the median plane. We suggest that heterochronic evolutionary change accounts for the compression of nymphal development into a single instar. We also suggest that this probably occurred at either the individual or colony level in this species.

Morphological and histological examination of polyphenic wing formation in the pea aphid Acyrthosiphon pisum (Hemiptera, Hexapoda)

“…The detailed morphological characteristics of thoracic structures were observed with a scanning electron microscopy JSM-5510LV (JEOL, Tokyo) (cf. Miura et al 2004). …”

Hidden aggression in termite workers: plastic defensive behaviour dependent upon social context

“…Soldiers, neotenics and pseudergates were used for the behavioural experiments. As in previous studies (Miura et al 2000, Miura et al 2004, seventh-instar larvae were regarded as pseudergates in this study. This species is considered to have two reproductive castes, primary reproductives and neotenics (supplementary or secondary reproductives) (Miura et al 2000).…”

“…1a) (Miura et 7 al. 2000, Miura et al 2004. In this species, true workers are absent, and elder juveniles, which are referred to as pseudergates (etymologically "false workers"), perform worker tasks.…”

“…Pseudergates are socially active and potentially capable of developing into imagos (Grassé & Noirot 1947;Noirot 1985;Thorne 1996;Parmentier & Roisin 2003). In H. sjostedti, after hatching from eggs, larvae undergo six moults before developing into pseudergates (Miura et al 2000, Miura et al 2004. While pseudergates are totipotent and capable of differentiating into reproductives or sterile soldiers, most remain pseudergates through stationary moults ( Figure 1a, Miura et al 2000, Miura et al 2004).…”

Histology of the hormone-producing glands in the damp-wood termite Hodotermopsis sjostedti (Isoptera, Termopsidae): A focus on soldier differentiation

“…Pseudergates can differentiate as well into alates through a single nymphal stage, into soldiers through the presoldier stage, or into neotenics (Miura et al, 2000;Miura et al, 2004). Pseudergate stationary molt or regressive molt of nymphs also occurs (GrassØ, 1982;Roisin, 1990;Koshikawa et al, 2001).…”