Accurate Batesian mimicry is known to impose constraints on some traits of the mimic, such as foraging or reproductive behaviour. It is not known whether life-history traits of inaccurate Batesian mimics are constrained as well. We studied selected life-history traits of three spider species, Liophrurillus flavitarsis, Phrurolithus festivus (both Corinnidae), and Micaria sociabilis (Gnaphosidae), that are inaccurate mimics of ants. Namely, we were interested in how myrmecomorphy (ant-like resemblance) constrains their circadian activity, trophic niche and reproductive behaviour. The spiders were found to have diurnal activity like their models, whereas their close relatives have nocturnal activity. The three mimics do not catch ants, nor do they use food resources of ants, but catch various tiny invertebrates that occur in the vicinity of their models. Their trophic niche seems to be constrained by occurrence among ants. Absence of courtship and long lasting copulation, in a position that does not provide protective resemblance, do not seem to be constrained by mimicry in the three species. Comparative analysis of fecundity in mimetic and non-mimetic spiders showed that clutch size is also not constrained. Unlike in accurate mimics, life-history traits of inaccurate myrmecomorphs appear not to be constrained. and Stano Pekár, Martin Jarab.
Competition is a major force organizing ant communities and results in co-occurring species evolving different strategies for foraging and use of space. Territorial species, as top dominants exclude each other, while shaping the local ant communities both qualitatively and quantitatively. In this study we examined how two territorial species, Formica polyctena and Lasius fuliginosus, can coexist in adjacent territories over long periods of time, and whether they affect co-occurring species of ants in different ways. Field observations in the absence and in the presence of baits were carried out around a L. fuliginosus nest complex surrounded by a polydomous F. polyctena colony in S Finland in 2007–2009. Both species controlled their territories, but were affected by changes in the abundance of the other species and the distance from L. fuliginosus’ main nest. They did not have the same effect on the subordinate species in the absence of baits, but the abundance of Myrmica spp. recorded at baits was negatively affected by both of the territorial species. The preferences of the different species for the artificial food sources differed: L. fuliginosus and F. polyctena preferred tuna to honey and Myrmica spp. honey to tuna. More individuals of the subordinate species were recorded in the territory of F. polyctena than of L. fuliginosus, although conflicts with this territorial species were also recorded. During the three years of the study almost no overlaps in the territories of the two territorial species were recorded, and there were mostly minor shifts in the boundaries of the territories. Differences between the two territorial species in their use of space and competitive effects ensured their coexistence at this particular site in Finland., Wojciech Czechowski ... [et al.]., and Obsahuje seznam literatury
Males in many beetles show horn or mandible dimorphism. The stag beetle Dorcus rectus was assumed to have dimorphic males, but in this species there are not two but three visually distinct mandibular phenotypes. The aim of this study is to determine if the three phenotypes represent an allometric trimorphism in this species by studying the scaling relationship between body length and mandible length in 148 adult males and 31 adult females. The relationship was fitted using the following four statistical models; a simple line, a logistic curve, a continuous segmented line and a discontinuous line. The best-fitting model for the males was a discontinuous line with two break points and that for the females a simple line. The male data was also well fitted by a logistic curve. The discontinuous linear model divided the males into three groups that were in good agreement with the three phenotypes. These results suggest that a subtle allometric trimorphism possibly exists in males of this species. Small males of this species have no distinct teeth on their mandibles, whereas small males of D. striatipennis and D. curvidens, which are closely related to D. rectus, have a pair of distinct teeth on their mandibles. The phylogenetic relationship of these Dorcus species suggests that the trimorphism in D. rectus may have arisen through the loss of teeth in small males., Yutaka Iguchi., and Obsahuje seznam literatury
In view of the extremely high metabolic rates involved, insect flight offers a fascinating model system for studying metabolism during exercise, including its regulation by metabolic neurohormones. In our laboratory the African migratory locust, Locusta migratoria, well-known for its long-distance flights, is used as an internationally recognized model insect. The insect is mass-reared under controlled conditions; its size permits convenient handling in vivo and in vitro, while flight activity can be easily evoked. In addition, research on this pest insect may be of economical importance.
A survey of the energy metabolism during locust flight is presented in Fig. 1. Flight activity stimulates the neurosecretory adipokinetic cells in the glandular lobes of the corpus cardiacum, a neuroendocrine gland connected with the insect brain, to release peptide neurohormones, the adipokinetic hormones (AKHs). The target for these hormones is the fat body. Via signal transduction processes, the action of the hormones ultimately results in the mobilization of both carbohydrate and lipid reserves as fuels for flight. Carbohydrate (trehalose) is mobilized from glycogen reserves, implying hormonal activation of the key enzyme, fat body glycogen phosphorylase, by phosphorylation. Similarly, on the lipid side, sn-1,2-diacylglycerol (DAG) is mobilized from stored triacylglycerol (TAG), by hormonal activation of the fat body TAG lipase. The carbohydrate and lipid substrates are transported in the hemolymph to the contracting flight muscles. Carbohydrate provides most of the energy for the initial period of flight, whereas at a later stage, lipid substrate in the blood is increased and gradually takes over. The transport of DAG requires specific lipoprotein carriers (lipophorins) which differ in several respects from the lipoproteins in mammals, and act as a lipid shuttle.
This review is focused on three interrelated topics, covering recent data on the biosynthesis and release of the AKHs, their signal transduction mechanisms in the fat body cells, and the changes in the lipophorin system induced by the AKHs during flight., Dick J. Van Der Horst, Wil J.A. Van Marrewijk, Henk G.B. Vullings, Jacques H.B. Diederen, and Lit
Several studies have demonstrated that the invasive ladybird Harmonia axyridis is a strong intra-guild predator of native species of ladybird. Laboratory studies have shown that H. axyridis can be an intra-guild predator of aphid predators other than coccinellids, including the hoverfly Episyrphus balteatus and lacewing Chrysoperla carnea. However, little is known about the effect of intra-guild predation (IGP) by H. axyridis on hoverfly and lacewing populations in the field. In the present study molecular analyses were used to detect the DNA of E. balteatus and C. carnea in the gut contents of H. axyridis. Primers for the syrphid and chrysopid prey were designed and feeding experiments performed to determine how long prey DNA remains detectable in the guts of this ladybird. DNA detection was influenced by the life stage of the predator and species of prey. Meal size did not affect detection time, except when fourth instar individuals of H. axyridis were fed 10 eggs or one second instar of C. carnea. Predator weight, sex and morpho-type (melanic/non-melanic) did not influence DNA detection. The half-life of the time for which the DNA of the prey remained detectable was calculated for each predator-prey combination, and ranged from 8.9 to 52.4 h. This method can be used to study the ecological importance of IGP by H. axyridis on aphidophagous predators other than coccinellids in the field., Brecht Ingels ... [et al.]., and Obsahuje seznam literatury
The aim of the present work was to identify cryptic species in the Anopheles maculipennis and Culex pipiens complexes and to study the genetic structure of the dominant mosquito species Ochlerotatus caspius (Diptera: Culicidae) in the Province of Alessandria close to the vast area untreated rice fields in Piedmont, NW Italy. With the help of PCR-RFLP analysis, four members of the Anopheles maculipennis complex were identified: A. messeae, A. maculipennis, A. sacharovi and A. atroparvus. Only C. pipiens f. molestus was identified in 11 habitats studied in Piedmont. Partial sequences of the cytochrome c oxidase subunit 1 (COI) mitochondrial gene and the second internal transcribed spacer (ITS2) of nuclear ribosomal RNA genes for Italian O. caspius are reported here for the first time. The results indicate that this species diverged from Iranian representatives of this species about one million years ago. The great diversity of mosquito species in Piedmont considerably increases the risk of vector-borne diseases. and Asghar TALBALAGHI, Elena SHAIKEVICH.
The ribosomal protein S6 kinase (S6K) plays a pivotal role in developmental processes and cell survival by participating in protein synthesis relevant signaling pathways. In the present study, an S6K gene (AccS6K-p70) was isolated and characterized from the Chinese honeybee, Apis cerana cerana (Fabricius) (Hymenoptera: Apidae), an important economic insect in the agricultural industry. The cDNA of AccS6K-p70 was 1683 bp in length and predicted to encode a protein of 467 amino acid residues. Sequence and structure analysis showed that there was a conserved catalytic domain in AccS6K-p70, whilst a phosphorylation site was found in the conserved part of the catalytic domain. Development relevant transcription factor binding sites found in the 5’-flanking region of AccS6K-p70 suggest that AccS6K-p70 might be involved in A. c. cerana development. Furthermore, quantitative PCR revealed that the expression levels of AccS6K-p70 were higher in head and thorax than in other tissues. The AccS6K-p70 was highly expressed in both larvae and adults compared with that in pupae, whilst expression of the gene was significantly down-regulated by hydrogen peroxide (H2O2) (although initially and slightly increased by it) and pyriproxyfen (a juvenile hormone analogue insecticide) stresses. These results suggest that AccS6K-p70 may play critical roles in developmental processes and cell survival in A. c. cerana, whilst both oxidative stress and pyriproxyfen may impair S6K-p70 mediated developmental processes by down-regulation of AccS6K-p70 expression., Yingqi Cai ... [et al.]., and Obsahuje seznam literatury
The two species of the genus Stomaphis feeding on oak and birch, respectively, although morphologically similar, are considered to be separate species. However, the birch-feeding S. betulae Mamontova is considered to be a synonym of the oak and birch feeding S. quercus (L.) by some authors. The purpose of this study was to determine whether the birch feeding and oak feeding populations attributed to S. quercus belong to the same species. The mitochondrial cytochrome-c oxidase I (COXI) and II (COXII) were used to determine whether these two populations differ. There are no significant differences in these markers from oak and birch feeding individuals, indicating that these populations are conspecific. However, morphologically and ecologically distinct populations of Stomaphis were discovered feeding on oak. The molecular analysis confirmed that these populations are distinct, which resulted in the description of the new oak-feeding species, Stomaphis wojciechowskii Depa, sp. n. This new species previously remained unrecognized due to its very cryptic mode of life., Lukasz Depa, Ewa Mroz, Karol Szawaryn., and Obsahuje seznam literatury
Mango orchards in Pakistan are attacked by the scale insect, Drosicha mangiferae (Hemiptera: Monophlebidae), commonly called the "mango mealybug". This insect is univoltine, active from December through May and targets multiple host plants. We used DNA nucleotide sequences to characterize and determine the phylogenetic status of D. mangiferae. Mango mealybugs were collected from several tree species from different localities and patterns of phylogenetic and genetic diversity were examined at both nuclear (18S, ITS1) and mitochondrial (COI) genes. Phylogenetic analysis confirms that the mango mealybug belongs to the family Monophlebidae. Minor genetic differences in both the ITS1 and the COI barcode region were noted among D. mangiferae collected from different geographic localities. These genetic differences revealed the existence of two genotypes of D. mangiferae that are region specific but not host-specific. and Muhammad Ashfaq, Jehan Ara, Ali Raza Noor, Paul D.N. Hebert, Shahid Mansoor.