EJE, vol. 99 (2002), issue 2

Proceedings of the Fourth European Workshop of Invertebrate Ecophysiology.


Eur. J. Entomol. 99 (2): 2002

The range of insect dormancy responses


Eur. J. Entomol. 99 (2): 127-142, 2002 | 10.14411/eje.2002.021

Insect dormancy responses, in the broad sense of modifications of development, are examined from a general perspective. The range of responses is extraordinarily wide because environments are diverse, different taxa have different evolutionary histories, adaptations are needed for both seasonal timing and resistance to adversity, and not only development but also many other aspects of the life-cycle must be coordinated. Developmental options are illustrated by examining the wide range of ways in which development can be modified, the fact that each individual response consists of several components, and the different potential durations of the life-cycle....

Ecophysiological consequences of variability in diapause intensity


Eur. J. Entomol. 99 (2): 143-154, 2002 | 10.14411/eje.2002.022

Diapause intensity (DI) is a physiological trait represented by the duration of diapause under given conditions of environment. In many species, it is highly variable, probably being controlled by multiple genes and tends to form a cline in response to the latitudinal gradient of selection pressure. DI clines could be established artificially by crossing between lines of a cricket selected for different levels of DI, indicating the importance of genetic factors in the adaptive variation of DI. However, DI may be modified in response to seasonal cues both before and after the onset of diapause. Polymorphism in the intensity of prolonged diapause may...

Photoperiodism and seasonal adaptations in some seed-sucking bugs (Heteroptera) in central Japan


Eur. J. Entomol. 99 (2): 155-161, 2002 | 10.14411/eje.2002.023

Photoperiodic responses and their adaptive significance were examined in Riptortus clavatus (Heteroptera: Alydidae), Plautia crossota stali, Dolycoris baccarum, Aelia fieberi, Nezara viridula, Nezara antennata, Graphosoma rubrolineatum, Dybowskyia reticulata, and Eurydema rugosum (Heteroptera: Pentatomidae) in the Kyoto-Osaka area, central Japan. All of these species overwinter as adults in diapause. Although they have similar feeding habits, their photoperiodic responses were quite different. Riptortus clavatus, P. c. stali, D. baccarum and N. viridula...

Controversial aspects of diapause development


Eur. J. Entomol. 99 (2): 163-173, 2002 | 10.14411/eje.2002.024

Although some parts of diapause development have been clarified up by endocrinologists, knowledge of the underlying processes remains insufficient. The survey of ecophysiological aspects of diapause development has thus to be limited to inputs and outputs from the blackbox. The terms diapause development, diapause intensity, post-diapause quiescence, horotelic processes of diapause, and tachytelic processes of diapause (reactivation) are defined. Andrewartha's term diapause development has been accepted because it shows diapause as a dynamic event.
In about the last 20 years, some views on diapause development have been updated, while others have...

Maternal age and endogenous variation in maternal influence on photoperiodic response in the progeny diapause in Trichogramma embryophagum (Hymenoptera: Trichogrammatidae)

Sergey Ya. REZNIK, Tatyana S. KATS, Taisiya Ya. UMAROVA, Nataliya D. VOINOVICH

Eur. J. Entomol. 99 (2): 175-179, 2002 | 10.14411/eje.2002.025

A laboratory study was carried out on photoperiodic control of prepupal diapause in the egg parasitoid Trichogramma embryophagum (Hartig). All experiments were conducted with an isofemale parthenogenetic strain. The maternal generation was reared at 20°C and photoperiods of L:D = 3:21, 6:18, 9:15, 12:12, 15:9, 18:6, 21:3 or 24:0. The tendency to diapause in the progeny was estimated by rearing the daughter generation at 15°C in the dark. Experiments revealed a long-day type response based on maternal influence on the progeny prepupal diapause. However, significant endogenous fluctuations in the pattern of the photoperiodic curve were revealed...

Physiology of cold-acclimation in non-diapausing adults of Pyrrhocoris apterus (Heteroptera)

Martin ©LACHTA, Petra BERKOVÁ, Jan VAMBERA, Vladimír KO©«ÁL

Eur. J. Entomol. 99 (2): 181-187, 2002 | 10.14411/eje.2002.026

Chill tolerance (time of survival at -5°C) increased in non-diapausing (reproducing) adults of Pyrrhocoris apterus after a gradual, 4-week-long decrease in ambient temperature from 25° to 0°C. The level of chill tolerance attained after cold-acclimation was considerably lower than that in similarly cold-acclimated diapausing adults. Some physiological changes accompanied the cold-acclimation, irrespective of developmental state (diapause vs. reproduction). They were: A decreased oxygen consumption, loss of body water, an increased haemolymph osmolality, an increased proportion of phosphatidylethanolamines vs. a decreased proportion of phosphatidylcholines...

Effects of host plant quality on overwintering success of the leaf beetle Chrysomela lapponica (Coleoptera: Chrysomelidae)


Eur. J. Entomol. 99 (2): 189-195, 2002 | 10.14411/eje.2002.027

I investigated effects of density-dependent variation in host plant quality on adult feeding and overwintering success of the leaf beetle Chrysomela lapponica L. During pre-overwintering period adult beetles were fed in the laboratory on host plants, Salix borealis, originating from (a) a site with low density population of C. lapponica, (b) a site with peak density of C. lapponica, and (c) a post-outbreak site. Beetles fed on plants from low density and peak density sites demonstrated similar performance, whereas on plants from post-outbreak site beetles fed longer, gained more weight, and experienced greater mortality...

Reaction norm in response to temperature may change to adapt rapid brood development to boreal and subarctic climates in Myrmica ants (Hymenoptera: Formicidae)


Eur. J. Entomol. 99 (2): 197-208, 2002 | 10.14411/eje.2002.028

Colonies of M. rubra, M. ruginodis and M. scabrinodis were collected in four geographic regions: Kiev, Ukraine (50.5°N, 30.5°E - first two species), Vladimir, Russia (56.2°N, 40.4°E - only last species), St. Petersburg, Russia (59.3°N, 30.3°E - all three species) and Chupa, Murmansk prov., Russia (66.3°N, 33.7°E - last two species). After artificial overwintering experimental cultures consisting of 150 workers and one queen were established and kept at 16, 18, 20, 22, 24 and 26°C under long (22 h) day lengths. The workers reared eggs laid by queens into rapid (non-diapause) brood pupae and diapause larvae, which were removed and...

Interrelations of gas exchange cycles, body movements and heartbeats in the foragers of bumblebee Bombus terrestris (Hymenoptera: Apidae) at low temperatures

Aare KUUSIK, Ants-Johannes MARTIN, Marika MÄND, Külli HIIESAAR, Luule METSPALU, Urmas TARTES

Eur. J. Entomol. 99 (2): 209-214, 2002 | 10.14411/eje.2002.029

Rhythmic body movements, cyclic gas exchange and heart activity were studied at low temperature (mostly at 5°C) in bumblebee Bombus terrestris foragers. Simultaneous measurements by means of an electrolytic respirometer combined with an optical system by infrared radiation, revealed a co-ordination between discontinuous gas exchange cycles and body rhythmic movements. No distinct correlation was found between intermittent heart activity and body movements. The carbon dioxide bursts were actively ventilated by abdominal vigorous pumping movements. These bursts followed each other with intervals of 25-30 minutes.
The periods of heart activity...

Tonic immobility in adult Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) evoked by mechanical and optical stimuli


Eur. J. Entomol. 99 (2): 215-219, 2002 | 10.14411/eje.2002.030

Adults of Colorado potato beetle Leptinotarsa decemlineata are very active at room temperature, and their almost continuous struggling in the respirometer prevents the measurements of the patterns of gas exchange, body movements and heartbeat. The tonic immobility of beetles was evoked by light flashes and by shaking as external stimuli. The immediate reaction to these stimuli was the reflexive closing of the spiracles and the cessation of CO2 release for some minutes, which was followed by a large burst of this gas. The state of the evoked tonic immobility did not influence heartbeat and abdominal pulsations, but the periodically...

Utilization of lipid for flight and reproduction in Spodoptera litura (Lepidoptera: Noctuidae)


Eur. J. Entomol. 99 (2): 221-224, 2002 | 10.14411/eje.2002.031

Research of the physiological traits of a long-distance migratory insect, the common cutworm Spodoptera litura, in relation to flight and reproduction, was focused on triacylglycerol (TG) levels and their fatty acid composition.
Tethered flight experiments demonstrated that three-day old male moths can fly more than 20 h. Among eight identified fatty acids of which the adult TG is composed, the ratios of the following unsaturated fatty acids, palmitoleic acid (C 16:1), oleic acid (C 18:1), linoleic acid (C 18:2) and linolenic acid (C 18:3), gradually declined with longer flight duration. On the other hand, the TG levels of non-flown males...

Latitudinal and local geographic mosaics in host plant preferences as shaped by thermal units and voltinism in Papilio spp. (Lepidoptera)


Eur. J. Entomol. 99 (2): 225-239, 2002 | 10.14411/eje.2002.032

Laboratory and field tests support the "voltinism-suitability hypothesis" of host selection at various latitudes as well as in local "cold pockets": The best hosts for rapid development will be selected by herbivorous insects under severe thermal constraints for completion of the generation before winter. Papilio canadensis and P. glaucus females do select the best hosts for rapid larval growth in Alaska and in southern Michigan, but not in northern Michigan and southern Ohio. In addition to latitudinal patterns, local host preferences of P. canadensis are described in relation to "phenological twisting" of leaf suitability for...

Food induced variation of thermal constants of development and growth of Autographa gamma (Lepidoptera: Noctuidae) larvae


Eur. J. Entomol. 99 (2): 241-252, 2002 | 10.14411/eje.2002.033

The development stages of a species may have an identical lower development threshold (LDT) and proportionally different durations. This phenomenon called "rate isomorphy" (RI) has been demonstrated for a number of insect species. In contrast, the growing day degrees accumulated over the period of larval development (sum of effective temperatures SET) should be plastic and vary with environment conditions. The prediction from RI is that, with changing conditions, the uniform LDT should be accompanied by differences in development time which remain proportional at different temperatures. This was tested by investigating the effect of diet on thermal...

The role of the subelytral cavity in water loss in the flightless dung beetle, Circellium bacchus (Coleoptera: Scarabaeinae)

Frances D. DUNCAN

Eur. J. Entomol. 99 (2): 253-258, 2002 | 10.14411/eje.2002.034

Circellium bacchus is a flightless telecoprid (ball-rolling) dung beetle, endemic to the afrotropical region, where it is found in a few restricted populations in the eastern Cape of South Africa. Its apterous condition and large size (mass ranges from 6 to 12 g) are considered to be adaptations to a semi-arid habitat. This beetle is active in the sun for long periods, walking between widely scattered dung pats, thus is under selection pressure to reduce water loss.
C. bacchus has eight spiracles on each side of the body. The metathoracic spiracle and six abdominal spiracles open into the subelytral cavity, which is closed. The mesothoracic...

Interactions of water, ice nucleators and desiccation in invertebrate cold survival

William BLOCK

Eur. J. Entomol. 99 (2): 259-266, 2002 | 10.14411/eje.2002.035

Four case studies are used to examine the relationships of water, ice nucleators and desiccation in the cold survival of invertebrates and the viability of frozen plant material: the freeze intolerant Antarctic springtail Cryptopygus antarcticus (Willem) (Collembola, Isotomidae), the freeze tolerant larvae of the fly Heleomyza borealis Boh. (Diptera: Heleomyzidae), the freeze intolerant Arctic springtail Onychiurus arcticus (Tullberg) (Collembola, Onychiuridae) and meristems of the currant Ribes ciliatum Humb. & Bonpl.(Grossulariaceae) from Mexico. Prevention of ice nucleation, lowering the water content by removal of...