Photoperiodic control of larval development and wing form in Modicogryllus sp. (Orthoptera: Gryllidae)

Abstract

The bivoltine cricket locally known as 'Tambo-Koorogi' (Modicogryllus sp.) hibernates as a half-grown larva, and shows a developmental response to changing as well as stationary photoperiod. At 25 ~ C, larvae matured in about 7-10 weeks in continuous or 16 h daily light, but took 10-20 weeks or more in 14 h and shorter days. A day of 15 h exerted an intermediate effect, giving a development time of 7-17 weeks. However, an increase in daylength from 12 to 15 h in the early larval life prevented diapause, while a decrease from 15 to 12 h retarded development more than a constant 12 h day. Short-winged adults occurred only when the photophase was 15 h or shorter, and their frequency increased with decreased daylength. Although the short-winged form took longer to mature than the long-winged form under the same conditions of photoperiod, delayed growth was not always associated with brachypterism.

Duration of development and number of nymphal instars are differentially regulated by photoperiod in the cricket Modicogryllus siamensis (Orthoptera: Gryllidae)

“…The results of transferring nymphs from long to short day conditions, and vice versa, confirm previous reports that short day conditions retard and the long day condi tions accelerate nymphal development (Masaki & Sugahara, 1992;Tanaka et al, 1999). They also indicate that short day conditions induce and maintain diapause and long day terminates it.…”

“…Once this instar is reached, the response is reversed: short days maintain and long days terminate diapause (Masaki & Oyama, 1963;Ismail & Fuzeau-Braesch, 1972, 1976Tanaka, 1978). This reversal of the photoperiodic response was not observed in M. siamensis: Long days and short days con sistently accelerated and decelerated, respectively, nymphal development.…”

“…These responses are thought to determine the time of adult emergence and oviposition of diapause eggs in autumn. In univoltine species that overwinter as nymphs, such as Gryllus campestris and Pteronemobius nitidus, short-days experienced in the early instars induce and maintain diapause but long-days experienced after a period of short-days terminate diapause (Masaki & Oyama, 1963;Ismail & Fuzeau-Braesch, 1972, 1976Masaki, 1972). Long-days increase not only the duration of nymphal development but also the number of instars in P. nitidus (Tanaka, 1979).…”

“…In bivoltine species, including Teleogryllus occipitalis, Dianemobius taprobanensis and Modico gryllus sp. (Miyagi strain, 38°N), nymphal development is promoted by long-days and retarded by short-days (Masaki & Ohmachi, 1967;Masaki, 1972;Masaki & Sugahara, 1992). In Modicogryllus sp., if the transfer from long-day to short-day or short-day to long-day con ditions is made early in nymphal development, the above effects on the duration of nymphal development can be reversed (Masaki & Sugahara, 1992).…”

Adaptive strategies of overwintering adults: Reproductive diapause and mating behavior in a grasshopper, Stenocatantops splendens (Orthoptera: Catantopidae)

“…Photoperiod as the most regular and dependable seasonal signal is the best predictor for weather conditions of the near future, and is thus often the main factor influencing the induction and maintenance of adult diapause in the fall (Tauber et al ., 1986; Danks, 1987; Mousseau & Dingle, 1991; Mousseau & Fox, 1998). Among those species that overwinter as diapause adults, some species are influenced by photoperiod in the spring– they maintain diapause at short photoperiods, but quickly resume reproduction at long photoperiods (e.g., Masaki & Oyama, 1963; Tauber & Tauber, 1975; see Tauber et al ., 1986). However, for some species, photoperiod is less important to the diapause maintenance of the overwintering adults and for instance, some species, especially some predatory species, require special food to start post‐diapause development (e.g., Hodek, 1971; Tauber & Tauber, 1973).…”