Gastrophysa Viridula Research Articles

A new microsporidian pathogen, Vairimorpha gastrophysae sp. nov., isolated from Gastrophysa viridula (Coleoptera: Chrysomelidae)

Gastrophysa viridula DeGeer 1775, the green dock leaf beetle, belongs to a group of beneficial insects, which can be used as a classical biological control agent against sorrels (Rumex sp., Polygonaceae). Therefore, any infection by pathogenic organisms in this beetle is undesirable. In the present study, a new microsporidian pathogen isolated from G. viridula was identified based on morphological and ultrastructural characteristics, supported with a molecular phylogenetic analysis. Light and transmission electron microscopy studies indicated that the microsporidium was polymorphic throughout its life cycle. Sporulation stages were not all in direct contact with the host-cell cytoplasm. The fresh single diplokaryotic spores of the secondary sporulation cycle had a long narrow morphology, measuring about 5 × 2.1 µm (n = 50). Octospores produced in the secondary sporulation cycle were also observed. Morphological and ultrastructural characteristics of the life cycle stages place it within the genus Vairimorpha. The phylogenetic tree constructed on the 16S rRNA gene sequence analysis supports the morphological and ultrastructural characteristics and indicates that the pathogen is closely related to the Vairimorpha clade of microsporidia. The pathogen is named Vairimorpha gastrophysae sp. nov.

Gastrophysa viridula (Coleoptera: Chrysomelidae) in the Czech Republic: Decline in a once abundant invasive oligophagous consumer of Rumex

While the progress of the spread of invasive species of insects in new geographical areas are usually intensively monitored, the decline of these species often escape attention and is poorly documented. In this study, we record the decline in abundance of Gastrophysa viridula (DeGeer), an invasive oligophagous consumer of dock (Rumex spp.). This species originally inhabited Alpine regions. In the late 1800s, G. viridula was recorded in montane areas in the Czech Republic and then throughout this country. Gastrophysa viridula was very abundant in 1995-1999, when we found it in all of the 177 stands of R. obtusifolius inspected in western Czech Republic. In a repeated study of its occurrence in the same area from 2019-2020, this species was present in < 30% of 434 of the stands inspected and was only abundant (≥ 55% of plants in the stand infested by G. viridula) in < 4% of these stands. Thus the local occurrence and abundance of G. viridula had decreased significantly. Of the possible reasons for this decline the most probable are the effect of climate warming on host plant seasonality, changes in agricultural use of grasslands and fragmentation of large stands of dock.

Beetle Orientation Responses of Gastrophysa viridula and Gastrophysa polygoni (Coleoptera: Chrysomelidae) to a Blend of Synthetic Volatile Organic Compounds.

The invasive weed Rumex confertus Willd. (mossy sorrel) is eaten and severely defoliated by oligophagous Gastrophysa viridula Deg. (dock leaf beetle) and Gastrophysa polygoni L. (knotweed leaf beetle). The most popular methods of plant protection involve the application of chemicals, but such methods often require repeated chemical treatments. Aromatic plants may constitute an eco-friendly alternative strategy owing to their repellent properties. To date, single compounds have been tested rather than blends; however, there is a need to investigate mixtures of compounds, because insects are subjected to blends of odors derived from their surrounding environments. The aim of the current study was to investigate behavioral responses of the dock leaf beetle and knotweed leaf beetle to a blend of synthetic plant volatile organic compounds. Plants were treated with standard repellents (a blend of volatile organic compounds) at two different concentrations (10 ng min-1 and 1,000 ng min-1). For further experiments, four rates (1 ng min-1, 10 ng min-1, 100 ng min-1, and 1,000 ng min-1 in 50 µl) were evaluated using a 4-way olfactometer. Leaf beetles of both sexes were repelled by the highest three concentrations tested. Female dock leaf beetles were also repelled by the lowest concentration tested, where individual components could have occasionally attracted insects. These results indicate a difference in responses to individual compounds and mixtures of compounds.

Potential of controlling selected weeds in Europe with insects

Weed control by insects is increasingly important, as chemical weed control (the use of herbicides) has an important impact on the environment and, consequently, on all organisms living there. The use of insects to control weeds thus represents an alternative to herbicides. The article presents the suppression of some widespread and persistent weeds in Europe with their natural enemies - insects. The following combinations presented below are: broad-leaved dock (Rumex obtusifolius L.) – Gastrophysa viridula (De Geer, 1775), curly dock (Rumex crispus L.) – Apion violaceum (Kirby, 1808), common ragweed (Ambrosia artemisiifolia L.) – Ophraella communa (LeSage, 1986) and Zygogramma suturalis (Fabricius, 1775), creeping thistle (Cirsium arvense (L.) Scop.) – Cassida rubiginosa (Müller, 1776), cleavers (Galium aparine L.) – Halidamia affinis (Fallen, 1807) and Sermylassa halensis (Linnaeus, 1767), common knotgrass (Polygonum aviculare L.) and black-bindweed (Fallopia convolvulus L.) – Gastrophysa polygoni (Linnaeus, 1758) and as the last one field bindweed (Convolvulus arvensis L.) – Galeruca rufa (Germar, 1824) and Tyta luctuosa (Denis in Schiffmuller, 1775).

Видове різноманіття безхребетних (Invertebrata) на маршрутах зоологічної практики студентів у Західній Чорногорі (Українські Карпати)

Since the second half of the 19th century invertebrate fauna of the Carpathians has been studied in detail by numerous scientists. The western branches of the Chornohora massif of the Ukrainian Carpathians has been attractive for the researchers of different groups of invertebrates. However, there is no possibility to evaluate their diversity dynamics in this area due to the lack of generalized comparative long-term data. With regard to that and considering the advantageous localization of the high-mountain biological station of Ivan Franko National University of Lviv as a convenient place for such investigation, the aim of our study was to describe the species diversity of invertebrates in the Western Chornohora for the initiation of stationary research of its dynamics. The material was collected by students according to the standard zoological methods during their field practice trips in July 2015–2019 on seven radial routes in various coenotic conditions and on different sites of the Western Chornohora. 149 species of invertebrate animals from 9 classes were identified in total. Insects considerably predominate among them by the species composition (about 80 %). The most common species of the 14 registered orders of Insecta represent Coleoptera (about 40 %), Hymenoptera and Lepidoptera (15 % each). Some of the invertebrate species were found on several different routes. For example, Gastrophysa viridula , Carabus auronitens , C. glabratus , Geotrupes stercorarius, Silpha carinata, Gordius aquaticus were sampled on three of them. The “Keveliv” route possesses the highest species richness of invertebrates (45 species) being almost twice higher than the average one (26 species), whereas the “Sheshul” route has the lowest richness (17 invertebrate species). The study revealed seven species listed in the Red Data Book of Ukraine ( Apatura iris , Aromia moschata , Chrysolina carpatica , Cordulegaster bidentata , Emus hirtus , Papilio machaon , Parnassius mnemosyne ), and three ones listed in the Red Data Book of the Ukrainian Carpathians ( Bombus wurflenii , Carabus transsylvanicus , Pieris bryoniae ). The presented findings can be used for the following analysis of invertebrate species diversity changes depending on habitats transformation with the consequent development of efficient biodiversity conservation measures in the Western Chornohora.

Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

Cellulose degradation in Gastrophysa viridula (Coleoptera: Chrysomelidae): functional characterization of two CAZymes belonging to glycoside hydrolase family 45 reveals a novel enzymatic activity.

Cellulose is a major component of the primary and secondary cell walls in plants. Cellulose is considered to be the most abundant biopolymer on Earth and represents a large potential source of metabolic energy. Yet, cellulose degradation is rare and mostly restricted to cellulolytic microorganisms. Recently, various metazoans, including leaf beetles, have been found to encode their own cellulases, giving them the ability to degrade cellulose independently of cellulolytic symbionts. Here, we analyzed the cellulosic capacity of the leaf beetle Gastrophysa viridula, which typically feeds on Rumex plants. We identified three putative cellulases member of two glycoside hydrolase (GH) families, namely GH45 and GH9. Using heterologous expression and functional assays, we demonstrated that both GH45 proteins are active enzymes, in contrast to the GH9 protein. One GH45 protein acted on amorphous cellulose as an endo-β-1,4-glucanase, whereas the other evolved to become an endo-β-1,4-xyloglucanase. We successfully knocked down the expression of both GH45 genes using RNAi, but no changes in weight gain or mortality were observed compared to control insects. Our data indicated that the breakdown of these polysaccharides in G. viridula may facilitate access to plant cell content, which is rich in nitrogen and simple sugars.

Investigating the efficiency of a bio-inspired insect repellent surface structure

Most insects with smooth or hairy adhesive pads have very little problems in attaching to smooth substrates. A careful selection of surface roughness, however, can effectively limit the contact area of the adhesive organs with the surface. In comparison to conventional toxin-based insect repelling methods, biologically inspired micro- and nanostructured insect repellent surface structures, thus, offer a great potential to effective and environmentally-friendly control insect pests.We here present a simple experimental approach to qualitatively and quantitatively analyse the efficiency of a micro- and nanorough surface structure. Nauphoeta cinerea and Gastrophysa viridula as model organisms for insects with smooth and hairy adhesive pads, respectively, were placed in an enclosed environment. The escape movements of freely running insects over either the repellent or a control surfaces were counted and analyzed in detail. The tested surface structures were able to significantly reduce the escape of cockroaches with smooth adhesive pads by 44.1%. Interestingly, the data indicates that N. cinerea might use mechanical cues from the antenna to discriminate between surfaces before making contact with the adhesive pads. G. viridula with hairy adhesive pads were not significantly affected by the surface structure.By carefully adjusting ‘critical’ surface topography parameters relevant for insect adhesion, more efficient and selective repellent surfaces might be achieved. Such nanostructure-based insect repellent surfaces could also help to utilize recruitment behavior of certain insect species and might present a novel approach to effectively control insect pests.

Evolution and functional characterization of CAZymes belonging to subfamily 10 of glycoside hydrolase family 5 (GH5_10) in two species of phytophagous beetles.

Hemicelluloses, such as xyloglucan, xylan and mannans, consist of a heterogeneous array of plant-derived polysaccharides that form the plant cell wall. These polysaccharides differ from each other in their structure and physiochemical properties, but they share a β-(1,4)-linked sugar backbone. Hemicelluloses can be hydrolyzed by plant-cell-wall-degrading enzymes (PCWDEs), which are widely distributed in phytopathogenic microbes. Recently, it has become apparent that phytophagous beetles also produce their own PCWDEs. Our previous work identified genes encoding putative mannanases belonging to the subfamily 10 of glycoside hydrolase (GH) family 5 (GH5_10) in the genomes of the leaf beetle, Gastrophysa viridula (Chrysomelidae, Chrysomelinae; one gene), and of the bean beetle, Callosobruchus maculatus (Chrysomelidae, Bruchinae; four genes). In contrast to proteins from other GH5 subfamilies, GH5_10 proteins are patchily distributed within the tree of life and have so far hardly been investigated. We addressed the following questions: Are beetle-derived GH5_10s active PCWDEs? How did they evolve? What is their physiological function? Using heterologous protein expression and enzymatic assays, we show that the G. viridula GH5_10 protein is an endo-β-1,4-mannanase. We also demonstrate that only one out of four C. maculatus GH5_10 proteins is an endo-β-1,4-mannanase, which has additional activity on carboxymethyl cellulose. Unexpectedly, another C. maculatus GH5_10 protein has evolved to use xylan instead of mannans as a substrate. RNAi experiments in G. viridula indicate (i) that the sole GH5_10 protein is responsible for breaking down mannans in the gut and (ii) that this breakdown may rather be accessory and may facilitate access to plant cell content, which is rich in nitrogen and simple sugars. Phylogenetic analyses indicate that coleopteran-derived GH5_10 proteins cluster together with Chelicerata-derived ones. Interestingly, other insect-derived GH5_10 proteins cluster elsewhere, suggesting insects have several independent evolutionary origins.

Development of structural colour in leaf beetles

Structural colours in living organisms have been observed and analysed in a large number of species, however the study of how the micro- and nano-scopic natural structures responsible of such colourations develop has been largely ignored. Understanding the interplay between chemical composition, structural morphology on multiple length scales, and mechanical constraints requires a range of investigation tools able to capture the different aspects of natural hierarchical architectures. Here, we report a developmental study of the most widespread strategy for structural colouration in nature: the cuticular multilayer. In particular, we focus on the exoskeletal growth of the dock leaf beetle Gastrophysa viridula, capturing all aspects of its formation: the macroscopic growth is tracked via synchrotron microtomography, while the submicron features are revealed by electron microscopy and light spectroscopy combined with numerical modelling. In particular, we observe that the two main factors driving the formation of the colour-producing multilayers are the polymerization of melanin during the ecdysis and the change in the layer spacing during the sclerotisation of the cuticle. Our understanding of the exoskeleton formation provides a unique insight into the different processes involved during metamorphosis.

Changes in tarsal morphology and attachment ability to rough surfaces during ontogenesis in the beetle Gastrophysa viridula (Coleoptera, Chrysomelidae)

Insects live in a three-dimensional space, and need to be able to attach to different types of surfaces in a variety of environmental and behavioral contexts. Adult leaf beetles possess great attachment ability due to their hairy attachment pads. In contrast, their larvae depend on smooth pads to attach to the same host plant. We tested friction forces generated by larvae and adults of dock leaf beetles Gastrophysa viridula on different rough surfaces, and found that adults generate much higher attachment to various substrates than larvae, but are more susceptible to completely losing attachment ability on surfaces with “critical” roughness. Furthermore, sex-specific setal morphology has the effect that attachment forces of male adults are generally higher than those of females when adjusted for body weight. The results are discussed in the context of development, ecology, and changing behavioral strategies of successive life stages.

Elasto-capillarity in insect fibrillar adhesion.

The manipulation of microscopic objects is challenging because of high adhesion forces, which render macroscopic gripping strategies unsuitable. Adhesive footpads of climbing insects could reveal principles relevant for micro-grippers, as they are able to attach and detach rapidly during locomotion. However, the underlying mechanisms are still not fully understood. In this work, we characterize the geometry and contact formation of the adhesive setae of dock beetles (Gastrophysa viridula) by interference reflection microscopy. We compare our experimental results to the model of an elastic beam loaded with capillary forces. Fitting the model to experimental data yielded not only estimates for seta adhesion and compliance in agreement with previous direct measurements, but also previously unknown parameters such as the volume of the fluid meniscus and the bending stiffness of the tip. In addition to confirming the primary role of surface tension for insect adhesion, our investigation reveals marked differences in geometry and compliance between the three main kinds of seta tips in leaf beetles.

Egg-hatching synchrony and larval cannibalism in the dock leaf beetle Gastrophysa viridula (Coleoptera: Chrysomelidae)

Females of leaf beetles and many other herbivorous insects lay eggs in coherent batches. Hatchlings emerge more or less simultaneously and often prey on their late-hatching clutchmates. It is not certain, however, whether this synchrony of hatching is a mere by-product of cannibalism or whether an additional synchronizing factor exists. The following simple experiment was aimed at determining the causal relationship between cannibalism and simultaneous larval emergence. Egg clutches of the dock leaf beetle Gastrophysa viridula were split into two halves. These halves were either kept as coherent groups in two separate dishes or, alternatively, only one half remained whole, whereas the other one was divided into single eggs, each of which was incubated in a separate dish. Halving of a clutch into coherent groups only slightly disrupted the synchrony of emergence. The consequence of individual isolation was more dramatic. Half-clutches consisting of disconnected solitary eggs required almost twice as much time for complete emergence of all larvae, which was significantly more than cannibalism as a sole synchronizing factor might explain. Moreover, survival rates were the same in coherent half-clutches (in the presence of cannibalism) and among isolated individuals. This group effect and the small contribution of cannibalism suggest the existence of an additional synchronizing factor. Possible mechanisms underpinning this phenomenon are discussed.

Insect adhesion on rough surfaces: analysis of adhesive contact of smooth and hairy pads on transparent microstructured substrates.

Insect climbing footpads are able to adhere to rough surfaces, but the details of this capability are still unclear. To overcome experimental limitations of randomly rough, opaque surfaces, we fabricated transparent test substrates containing square arrays of 1.4 µm diameter pillars, with variable height (0.5 and 1.4 µm) and spacing (from 3 to 22 µm). Smooth pads of cockroaches (Nauphoeta cinerea) made partial contact (limited to the tops of the structures) for the two densest arrays of tall pillars, but full contact (touching the substrate in between pillars) for larger spacings. The transition from partial to full contact was accompanied by a sharp increase in shear forces. Tests on hairy pads of dock beetles (Gastrophysa viridula) showed that setae adhered between pillars for larger spacings, but pads were equally unable to make full contact on the densest arrays. The beetles' shear forces similarly decreased for denser arrays, but also for short pillars and with a more gradual transition. These observations can be explained by simple contact models derived for soft uniform materials (smooth pads) or thin flat plates (hairy-pad spatulae). Our results show that microstructured substrates are powerful tools to reveal adaptations of natural adhesives for rough surfaces.

The effect of alpine ski-slopes on epigeic beetles: does even a nature-friendly management make a change?

Unique alpine ecosystems are threatened by skiing activities all over the world. We studied the effect of alpine ski-slopes on epigeic beetles by pitfall trapping in the Praděd National Nature Reserve (Czech Republic) where the management of ski-slopes has never caused any disturbance to the vegetation cover. Using a mixed modelling approach, we demonstrate a significant effect of ski-slope management on the epigeic beetle community, including its functional diversity. Beetle species responded to the ski-slope individually. We found a noticeable decline in the abundance of most species in the patches with artificially increased accumulation of snow, i.e. close to the interior edges of the ski-slopes. Above all, the ski-slopes were not preferred by relict species such as Neagolius limbolarius, Minota carpathica and Liotrichus affinis but vagile widespread carabids (Amara lunicollis, Poecilus versicolor) and herbivores associated with nitrophilous plants (Gastrophysa viridula) were more abundant on the ski-slopes. A few stenotypic carnivorous and herbivorous species were found on the ski-slopes. A high abundance of mountain herbivores such as leaf beetle Timarcha metallica reflected an increased occurrence of their host plants and carnivores such as Carabus sylvestris and Pterostichus oblongopunctatus could prefer ski-slopes due to the locally increased food supply. With respect to both uniqueness of alpine communities and to the small extent of alpine treeless zone, we recommend considering very cautiously any potential expansion of ski resorts, even those with reasonable ‘nature-friendly’ practices.

Sperm morphology and phylogeny of lagriids (Coleoptera, Tenebrionidae)

The systematics of tenebrionids remain unclear, principally at the subfamily level, as is the case of the Lagriinae. Considering that sperm morphology has contributed to the various insect group phylogenies, in this work we describe the structure and ultrastructure of these cells in Lagria villosa. Sperm in this species exhibit a strong morphological similarity to those of Tenebrio molitor and Tribolium castaneum, the only two species of Tenebrionidae with previously described sperm. In tenebrionids, the flagellar components offer good diagnostic characters, e.g. the symmetry of mitochondrial derivatives in L. villosa differentiates sperm of this species from those of Te. molitor and Tr. castaneum. However, the lateral association of the nucleus with flagellar components, the form of accessory bodies, and the presence of material connecting the axoneme to the accessory bodies and mitochondrial derivatives indicate that the three species form a sister group. Therefore, the sperm morphology of L. villosa support lagriid beetles as a subfamily (Lagriinae) of Tenebrionidae.

Beetles Do It Differently: Two Stereodivergent Cyclisation Modes in Iridoid‐Producing Leaf‐Beetle Larvae

Larvae of the Chrysomelina species Phaedon cochleariae, Hydrothassa marginella, Phratora vulgatissima, Gastrophysa viridula, Gastrophysa atrocyanea, Gastrophysa cyanea and Gastrophysa polygoni produce the iridoid chrysomelidial (1) to defend themselves against predators. Feeding experiments with a deuterated precursor ([(2)H(5)]8-hydroxygeraniol 9) and in vitro isotope exchange experiments with defensive secretion in (2)H(2)O revealed differences in the cyclisation of the ultimate precursor 8-oxogeranial (8) to 1, between members of the genus Gastrophysa and all other species. In P. cochleariae, H. marginella and P. vulgatissima 1 is most likely produced by a Rauhut-Currier-type cyclisation via a "transoid dienamine", with loss of a single deuterium atom from C(4) of the precursor. In contrast, members of the genus Gastrophysa cyclise 8 via a "cisoid dienamine" intermediate, with exchange of all three deuterium atoms from the methyl group at C(3). To study whether the different cyclisation modes influence the stereochemistry of 1, the absolute configuration of 1 of the larvae was determined by GC-MS on a chiral column. In accordance with literature (J. Meinwald, T. H. Jones, J. Am. Chem. Soc. 1978, 100, 1883 and N. Shimizu, R. Yakumaru, T. Sakata, S. Shimano, Y. Kuwahara, J. Chem. Ecol. 2012, 38, 29), we found (5S,8S)-chrysomelidial (1) in H. marginella and P. vulgatissima, but P. cochleariae and all investigated members of the genus Gastrophysa synthesise (5R,8R)-chrysomelidial (1).

Dock Leaf Beetle, Gastrophysa viridula Deg., Herbivory on the Mossy Sorrel, Rumex confertus Willd: Induced Plant Volatiles and Beetle Orientation Responses

The invasive weed Rumex confertus Willd. (mossy sorrel) is fed upon and severely defoliated by Gastrophysa viridula Deg. (dock leaf beetle). We report volatile organic compound (VOC) induction when one leaf on R. confertus was damaged by G. viridula adults to better understand plant responses to herbivory. The R. confertus volatile blend induced by G. viridula feeding included three green leaf volatiles (GLVs; (Z)-3-hexenal, (Z)-3-hexen-1-ol, (Z)-3-hexen-1-yl acetate) and terpenes (linalool, s-caryophyllene, s-farnesene). Overall, R. confertus that had been damaged by G. viridula released far greater concentrations of these six VOCs than control plants. Male and female of G. viridula had no significant attraction or repulsion to (Z)-3-hexen-1-ol or s-caryophyllene. A significantly greater proportion of female and male beetles were attracted to (Z)-3-hexenal (5 ng×min -1 = 300 ng×hr -1 ) and (Z)-3-hexen-1-yl acetate (5 and 25 ng×min -1 ), in the range of induced concentrations emitted by a single injured leaf.

Sexual dimorphism in photoperiodic plasticity of body mass in the green dock leaf beetle Gastrophysa viridula (Coleoptera, Chrysomelidae)

Sexual dimorphism in body mass was studied in prepupae, pupae and immature adults of the green dock leaf beetle Gastrophysa viridula under a constant temperature of 24°C and two photoperiods (12L:12D and 22L:2D). Females were significantly heavier compared to males at all the three developmental stages; just after emergence from pupae they weighed, on average, 11.4 mg, while males—10.3 mg. Sex differences in photoperiodic body mass plasticity were revealed: under short-day conditions pupal and adult mass in females was significantly higher compared to long day, but not in males. Such a response to short day (the factor inducing reproductive diapause in this species) is likely to promote accumulation of greater amount of nutrients by females which is necessary for earlier oviposition after overwintering.

Control of preimaginal development by photoperiod and temperature in the dock leaf beetle Gastrophysa viridula (De Geer) (Coleoptera, Chrysomelidae)

Development times of preimaginal stages and immature adult body mass of the dock leaf beetle Gastrophysa viridula from Bryansk (53°N, 34°E) were determined at six constant temperatures ranging from 16 to 26°C and at two photoperiods, 12L: 12D or 22L: 2D. The lower developmental threshold (LDT) and sum of degreedays (SDD) were calculated for eggs, larvae, and pupae; the values for the total preimaginal development were 7.9°C and 274.8 °C×d, respectively. The thermal reaction norms for preimaginal development were not affected by photoperiod, although the adult body mass was on average greater under short-day conditions. Our results confirm the previously published data on G. viridula concerning diapause induction by shorter daylengths, greater body mass under lower temperatures, and narrowing of the thermal optimum range during preimaginal development. The thermal reaction norms for larval development were shown to be the same in individuals that died during the pupal stage, and in those that successfully emerged as adults. Our results are more precise than the previous data on this species due to a larger sample size, careful control of rearing conditions, and the use of an alternative method for calculating LDT and SDD. In particular, a more accurate estimation of LDTs allowed us to demonstrate that rate isomorphy was violated in this species, contrary to what had been stated by Honěk and co-authors (2003).