EJE, vol. 100 (2003), issue 2

Proceedings of the Second Czech-Japanese Seminar on Entomology. Insect Photoperiodism and Rhythmicity.


Eur. J. Entomol. 100 (2): 2003

Studying insect photoperiodism and rhythmicity: Components, approaches and lessons


Eur. J. Entomol. 100 (2): 209-221, 2003 | 10.14411/eje.2003.036

Components of daily and seasonal timing systems in insects are reviewed. Photoperiod indicates seasonal position reliably, but signals can be much modified by habitat, latitude and season. Several receptor features and pigment systems are known, with different daily, seasonal and general functions, including differences between circadian and seasonal reception. Clocks can serve several different purposes, functioning as daily oscillators, interval timers or through successive requirements. The molecular functioning of circadian clocks is best known, but even so there is considerable complexity and diversity and much remains to be discovered. We know...

Role of water and moisture in diapause development (A review)


Eur. J. Entomol. 100 (2): 223-232, 2003 | 10.14411/eje.2003.037

While observational studies led to the assumption that water or moisture (W/M) is a prerequisite for diapause development, the experimental research indicates rather the opposite: usually W/M is needed as late as for the post-diapause resumption of morphogenesis. Recent examples for this type of regulation of dormancy are given: Eggs of the tettigoniid Stictophaula armata, eggs of the grasshopper Oedaleus senegalensis, adults of the bruchid Bruchidius atrolineatus, adults of the endomychid Stenotarsus subtilis (= S. rotundus). In the late diapause of the noctuid Busseola fusca and in eggs of the chrysomelid...

Phenotypic plasticity and development of cold-season insects (Coleoptera: Leiodidae) and their response to climatic change

Werner TOPP

Eur. J. Entomol. 100 (2): 233-243, 2003 | 10.14411/eje.2003.038

Cold-season beetles, Catops nigricans Spence, Choleva agilis Illiger and Choleva elongata Payk., i.e. beetles which start to lay eggs in autumn, which are active during the winter in the adult stage and develop from the egg stage to the adult stage mainly during the winter months, were collected from various locations in north-western Europe and reared in the laboratory at varying temperatures and photoperiods.
Reproduction of all species started in autumn and continued during the winter months. Highest reproductive and survival rates occurred at low temperatures and within a small thermal window ranging from 5° to 10°C: The...

Enhanced expression of genes in the brains of larvae of Mamestra brassicae (Lepidoptera: Noctuidae) exposed to short daylength or fed Dopa

Masahide URYU, Yohsuke NINOMIYA, Takeshi YOKOI, Seiji TSUZUKI, Yoichi HAYAKAWA

Eur. J. Entomol. 100 (2): 245-250, 2003 | 10.14411/eje.2003.039

The cabbage armyworm, Mamestra brassicae, enters diapause in the early pupal stage. Pupal diapause is induced by rearing the larvae under short day lengths. We previously demonstrated that feeding Dopa during last larval instar induces pupal diapause even under long day lengths. In order to elucidate the mechanism by which pupal diapause is induced after experiencing short day lengths or fed Dopa under long day lengths, we analyzed gene expression in the brain of M. brassicae larvae under both of these conditions using a subtractive hybridization technique. After the secondary screen, 49 clones and 28 clones were identified as short day...

Sarcotoxin II from the flesh fly Sarcophaga crassipalpis (Diptera): A comparison of transcript expression in diapausing and nondiapausing pupae


Eur. J. Entomol. 100 (2): 251-254, 2003 | 10.14411/eje.2003.040

Many stress-induced genes, including those related to the insect humoral immune response, are upregulated during diapause even in the absence of stress. We further test the relationship between stress genes and diapause in Sarcophaga crassipalpis by cloning sarcotoxin II, a member of the attacin family, and examining its expression pattern in relation to pupal diapause. Unlike several other stress-related genes, sarcotoxin II is not developmentally upregulated during diapause, but it remains fully responsive to immune challenge. Interestingly, the elevation of sarcotoxin II mRNA in response to body wall injury, but not immune...

TIMELESS: A link between fly's circadian and photoperiodic clocks?

Jaroslav PAVELKA, Kimio SHIMADA, Vladimir KOSTAL

Eur. J. Entomol. 100 (2): 255-265, 2003 | 10.14411/eje.2003.041

Potential involvement of circadian clock genes in so far unknown mechanism of photoperiodic time measurement is an important question of insect life-cycle regulation science. Here we report about the cloning of full-length cDNA of the structural homologue of the Drosophila's timeless gene in Chymomyza costata. Its expression was compared in two strains: a wild-type strain, responding to short days by entering larval diapause and a npd-mutant strain, showing no photoperiodic response. The timeless mRNA transcripts were not detectable by Northern blot analysis in the fly heads of npd-mutants, while they were...

Period gene expression in relation to seasonality and circadian rhythms in the linden bug, Pyrrhocoris apterus (Heteroptera)


Eur. J. Entomol. 100 (2): 267-273, 2003 | 10.14411/eje.2003.042

Wild females of Pyrrhocoris apterus exhibit seasonal changes in neuroendocrine activity and, consequently, reproduction. Long days (18 h light/6 h dark) (LD) stimulate reproduction, whereas short days (12 h light/12 h dark) (SD) induce reproductive arrest (diapause). This study reveals how photoperiod influences the expression of the circadian clock gene, period (per) in the insect's head. There is only a weak diurnal rhythm in per mRNA expression under LD and SD. However, levels of per mRNA are consistently higher (up to 10-fold) under SD than under LD. The influence of photoperiod on per gene expression is...

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


Eur. J. Entomol. 100 (2): 275-281, 2003 | 10.14411/eje.2003.043

The effect of photoperiod on nymphal development in the cricket Modicogryllus siamensis was studied. In constant long-days with 16 hr light at 25°C, nymphs matured within 40 days undergoing 7 moults, while in constant short-days with 12 hr light, 12~23 weeks and 11 or more moults were necessary for nymphal development. When nymphs were transferred from long to short day conditions in the 2nd instar, both the number of nymphal instars and the nymphal duration increased. However, only the nymphal duration increased when transferred to short day conditions in the 3rd instar or later. When the reciprocal transfer was made, the accelerating effect of long-days...

Immunohistochemical localization of clock proteins (DBT and PER), and [His7]- and [Arg7]-corazonins in the cerebral ganglia of Bombyx mori: Are corazonins downstream regulators of circadian clocks?


Eur. J. Entomol. 100 (2): 283-286, 2003 | 10.14411/eje.2003.044

The brain and subesophageal ganglion (BR-SG) of the commercial silk worm, Bombyx mori, were stained immunohistochemically at the larval stage for circadian clock neurons with antibodies against Doubletime (DBT) of B. mori and Period (PER) of Periplaneta americana. The BR-SGs were also stained with antisera against [Arg7]-corazonin, which has been known to be present in B. mori and co-localized with PER in Manduca sexta, and against [His7]-corazonin, a homolog identified in other species. From co-localization of [Arg7]-corazonin and PER-like reactivities in the pars lateralis,...

Photoperiodic clock of diapause termination in Pseudopidorus fasciata (Lepidoptera: Zygaenidae)

Aiqing LI, Fangsen XUE, Ai HUA, Jianjun TANG

Eur. J. Entomol. 100 (2): 287-293, 2003 | 10.14411/eje.2003.045

Photoperiodic control of diapause termination was systematically investigated in Pseudopidorus fasciata. In 24 h light-dark cycles, the rate of diapause termination in this species depended on photoperiod. The critical night length (CNL) for diapause termination was 10 h, 0.5 h shorter than that for diapause induction. Night-interruption experiments with T = 24 showed that diapause was effectively terminated when the scotophases separated by light pulse were shorter than the critical night length (10 h); no developing individuals were found if the duration of the pre-interruption scotophase or the post-interruption scotophase exceeded the CNL....

Effect of temperature on development and reproduction in Gastrophysa viridula (Coleoptera: Chrysomelidae)


Eur. J. Entomol. 100 (2): 295-300, 2003 | 10.14411/eje.2003.046

The duration of development, reproduction and longevity of Gastrophysa viridula (DeGeer) was measured at constant temperatures and a long day photoperiod. At 18, 21.5, 25, and 28°C the average duration of development of the egg, larval and pupal stages and total development time (28.2, 21.6, 16.1, 15.0 days) decreased with temperature but the proportion of time spent in the egg, larval and pupal stages did not significantly change with temperature. Total development required 304.6 day degrees above the lower development threshold of 7.1°C. Pre-adult mortality and the rate of oviposition increased, and the duration of oviposition decreased with...

Photoperiodic receptor in the nymph of Poecilocoris lewisi (Heteroptera: Scutelleridae)

Ryo MIYAWAKI, Shinichi I. TANAKA, Hideharu NUMATA

Eur. J. Entomol. 100 (2): 301-303, 2003 | 10.14411/eje.2003.047

The receptor for photoperiodism in nymphs of Poecilocoris lewisi was examined using a phosphorescent paint, which absorbs light energy and emits phosphorescence in the dark. This species shows a facultative diapause in the fifth (final) nymphal instar and its induction is primarily controlled by photoperiod in the fourth instar. The incidence of diapause in the fifth instar was determined after exposing selected regions of the body surface to a longer photophase than the rest by applying a phosphorescent paint in the fourth instar. The incidence of diapause was significantly lower in insects with their compound eyes painted than in control insects...