1_Monogeny, the production of unisexual broods by individual females, is widely recorded in gall midges (Diptera: Cecidomyiidae). Theoretical models propose that the adjustment of offspring sex ratio by females may pre-dispose the evolution of monogeny in gall midges however empirical studies in this field are superficial. Expressed more simply, monogeny may enable individual female gall midges to decrease or increase the number of male and female progeny they produce in response to changes in environmental conditions. Host quality/size is repeatedly reported to influence sexual investment in insects in terms of sex ratio adjustment. In this paper, we examined the sex ratio of the offspring of the monogenous predatory gall midge Aphidoletes aphidimyza attacking low and high abundances of the cotton aphid, Aphis gossypii. Two consecutive generations of female gall midges were presented with either a low or high abundance of aphids in each generation and the sex ratio of their progenies determined. There was no difference between the sex ratio of the progenies that developed on the high or low abundance of A. gossypii in the two generations. Apparently, the females did not regulate the number of female and male progenies, or adjust the numbers of male or female’s eggs they produced in response to the changes in the abundance of prey. Results of this study do not support the theory of sex ratio regulation proposed for monogenous gall midges. It is likely that the skewed sex ratio in most species of monogenous gall midges is a consequence of differential mortality of male and female progenies under harsh conditions., 2_The finding that male and female larvae did not differ in the number of aphids they require to complete their development supports this claim., Seyed Mohammad Tabadkani, Ahmad Ashouri, Farhad Farhoudi., and Obsahuje seznam literatury
The United Nations Conference on Environment and Development (Earth Summit) held in Rio de Janeiro in June 1992 was an undisputed milestone in environment protection and management. The ambitious target to achieve by 2010, a significant re - duction in the current rate of biodiversity loss at the global, regional and national level, was not met. In October 2010, the Parties to the Convention on Biological Diversity adopted a revised and updated Strategic Plan for Biodiversity for 2011–20. The forthcoming UN Conference on Sustai - nable Development is going to aim particularly at the Green Economy in the context of sustainable development and poverty eradication. and Jan Plesník.
A new genus and species of Hemiptera: Heteroptera: Enicocephalomorpha: Aenictopecheidae: Aenictopecheinae, Ulugurocoris grebennikovi gen. et sp. n., based on micropterous females from Tanzania, Uluguru Mts, Budunki, is described and differentiated. The males are probably macropterous. Some general aspects of morphology of U. grebennikovi are discussed in a broader context, such as presence of cephalic trichobothria (suggested to be a groundplan character of Heteroptera), presence of “gular sulci” (suggested to have an ecdysial function), lack of cephalic neck (symplesiomorphy with other Hemiptera), presence of posterior lobe of pronotum associated with the epimeroid (a new term for so called “proepimeral lobe”), and presence of notopleural sulcus on the propleuron. Diagnostic characters of the Aenictopecheinae are summarized and distribution of their seven genera is reviewed. Ulugurocoris grebennikovi is the first representative of the basal family Aenictopecheidae in the Afrotropical Region. The type locality is situated in the Eastern Arc Mountains (Tanzania), a recently identified hotspot of Afrotropical diversity characterized by a high degree of endemism caused by high rates of speciation combined with low rates of extinction. A brief characterization of the area is provided., Pavel Štys, Petr Baňař., and Obsahuje seznam literatury
Velia currens (Fabricius, 1794) and V. gridellii Tamanini, 1947 are two South European species of Veliidae, whose ecology and behaviour are poorly known. The aims of this study were to investigate their life histories, quantify occurrence of wing polymorphism and gather information on their degree of co-occurrence. Nine different populations were regularly surveyed from April to November 2010. Furthermore, a dataset containing information on the occurrence of the two species and the presence of winged morphs at 294 sites was compiled from museum collections, private collections and published literature. No evidence for multivoltinism was detected in either species. However, oviposition and and/or hatching were protracted in time so that early-instar nymphs and adults co-occurred up to midsummer. Although their distributional ranges completely overlap at a large spatial scale, the two species co-occurred only rarely at the same sites and the degree of co-occurrence was lower than expected by chance. Winged specimens were rarely recorded. At least in V. gridellii, the numbers of winged individuals were inversely related to the altitudes of the sites. During the summer, when some of the streams surveyed dried up, several specimens were found in an apparent state of lethargy, under stones. It is hypothesized that the ability to aestivate, coupled with the ability to walk from one site to another may reduce the advantage associated with producing winged forms and account for the low rate of occurrence of macropterism in these species., Fabio Cianferoni and Giacomo Santini., and Obsahuje seznam literatury
Results of studies on prey suitability for generalist predators are important for efficient mass rearing and implementing Integrated Pest Management Programmes (IPM). The green lacewing, Chrysoperla sinica (Tjeder), is a polyphagous natural enemy attacking several pests on various crops in China. We investigated the effect of feeding it different species of prey on its pre-imaginal development, survival, adult longevity and fecundity under laboratory conditions. The prey species tested were nymphs of Aphis glycines Matsumura, cotton aphid Aphis gossypii Glover, peach aphid Myzus persicae Sulzer, corn aphid Rhopalosiphum maidis Fitch and cowpea aphid Aphis craccivora Koch, and eggs of the rice grain moth, Corcyra cephalonica Stainin. None of these species of prey affected the pre-imaginal survival or percentage survival of the eggs of the predator. However, eggs of C. cephalonica and nymphs of M. persicae and A. glycines were the best of the prey species tested, in that when fed on these species the pre-imaginal developmental period of C. sinica was shorter and its adult longevity, fecundity and percentage survival greater than when fed the other species of prey. In contrast, when fed nymphs of A. craccivora the pre-imaginal development period was longer, adult longevity shorter and fecundity lower. These findings could be helpful in defining more optimum conditions for the mass rearing of C. sinica for use in integrated pest management (IPM) programmes for various crops., Niaz Hussain Khuhro ... [et al.]., and Obsahuje seznam literatury
Age of host eggs can be a limiting factor for egg parasitoids. It is expected that old eggs are less preferred by egg parasitoids, which can discriminate between eggs of different ages by using chemical cues. The objective of this study was to determine the preference, development and arrestment of Telenomus remus Nixon (Hymenoptera: Scelionidae) parasitizing Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) eggs of different ages. This egg parasitoid preferred to parasitize 1- and 2-day-old eggs rather than 3-day-old eggs in choice and no-choice assays. However, although the percentage emergence of parasitoids is significantly lower from 2- and 3-day-old eggs, the sex ratio and developmental time are unaffected. Parasitoids spent longer searching substrates impregnated with extracts of 1- and 2-day old eggs than 3-day-old eggs. Our results reveal that T. remus is able to distinguish the most suitable (1-day-old) from the least suitable (3-day-old) host eggs, but unable to recognize the unsuitability of intermediate aged eggs. Egg arrestants may be responsible for the preference of T. remus for ovipositing in 1- and 2-day old eggs., Maria Fernanda Gomes Villalba Penaflor ... [et al.]., and Obsahuje seznam literatury
The effect of different host plants on Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) body size was investigated. Thrips from three different populations, from the Netherlands, Italy, and USA, achieved greater body sizes when reared on cucumber than on bean. The same thrips grew larger when reared on susceptible than on resistant cucumber. On the latter, reproduction was reduced, suggesting that smaller thrips have a lower reproduction. However, no evidence was found for a correlation between size and reproduction in experiments with thrips from four different populations, from the Netherlands, New Zealand, France, and USA that differed significantly in body size. Also when individual thrips from the four populations were tested, there was no correlation between size and reproduction. It is concluded that resistant cucumber affects both size and reproduction of F. occidentalis. However, lower reproduction in general is not associated with smaller body size., Willem Jan de Kogel, Domenico Bosco, Marieke van der Hoek, Chris Mollema, and Lit
The occurrence of melatonin is known in nearly all organisms, but nothing is known exactly about its function outside of vertebrates. Long-term perifusions as well as short-term batch incubations of brains and moulting glands of the cockroach Periplaneta americana were used to identify the effect of melatonin on the release of prothoracicotropic hormone, a glandotropic neuropeptide in the brain, which stimulates the production of the moulting hormone ecdysone in the moulting gland. This is the first experimental evidence of a neurohormonal releasing effect of melatonin in the insect nervous system., Klaus Richter, Elmar Peschke, Dorothee Peschke, and Lit
Reduced oviposition by ladybirds in the presence of tracks of fourth instar larvae owing to the presence of oviposition deterring pheromones is well established across many genera. However, deterrence, if any, by other life stages has not been well investigated, in particular the effect of conspecific presence. The present study investigates the effects of conspecific presence and semiochemicals of conspecific life stages (eggs, fourth instar larvae, pupae, adult males and females) on oviposition by five ladybird (Coleoptera: Coccinellidae) species, viz. Coccinella septempunctata, Coccinella transversalis, Cheilomenes sexmaculata, Propylea dissecta and Anegleis cardoni. Results reveal that the presence of life stages inhibits oviposition and the inhibition is density-dependent, although the degree of inhibition is species-specific. Surface semiochemicals of eggs and larval and adult tracks also show density-dependent inhibitory effects. Moreover, the semiochemicals in tracks (oviposition deterring pheromones) and egg surface semiochemicals are not similar, indicating semiochemical parsimony. Of all species tested, C. transversalis and C. septempunctata were the most and the least responsive to both conspecific presence and semiochemicals, respectively., Geetanjali Mishra ... [et al.]., and Obsahuje seznam literatury