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It has long been assumed, since the early works of Mather, that the centromere plays a central role in chiasma position determination, so much so that in all sequential models chiasma determination was supposed to start or finish ...
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It has long been assumed, since the early works of Mather, that the centromere plays a central role in chiasma position determination, so much so that in all sequential models chiasma determination was supposed to start or finish at this point. More specifically, it has been asssumed that the centromere acts as a barrier to the transmission of interference, so that a chiasma in the vicinity of a centromere would not affect the probability elf chiasma formation across this point. Some statistical analyses seemed to ratify this supposition. However, a reassessment of the literature led us to the conclusion that the statistical analyses that were not flawed were consistent in showing that interference may net across the centromere. Using large sets of chiasma data from the grasshoppers Leptysma argentina and Chorthippus brunneus and applying statistical approaches that involved either the calculation of coincidence or correlating the distances between the centromere and the nearest chiasma in either arm, it is concluded: 1 that interference nets across the centromere; 2 that the action of interference is not changed by the presence of an intervening centromere. [References: 46]
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The semiaquatic grasshopper Cornops aquaticum is native to South America, with a distribution as far south as the Argentinean pampas and as far north as the Gulf of Mexico. This grasshopper is being proposed as a form of biologica...
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The semiaquatic grasshopper Cornops aquaticum is native to South America, with a distribution as far south as the Argentinean pampas and as far north as the Gulf of Mexico. This grasshopper is being proposed as a form of biological control agent for the invasive aquatic macrophyte (Eichhornia crassipes) in South Africa. The results of a molecular study (six microsatellite loci) conducted on 11 C. aquaticum populations is presented. Unlike in contiguous mainland South American populations, we found genetic diversity to be lowest in a South African quarantine population, with reduced values in two other isolated populations from South America. In addition, Fst/Rst/analysis of molecular variance and Bayesian cluster analysis suggested high levels of connectivity between mainland populations. The implications of these findings and their relationship to those of a recent morphological study suggest that the suitability of C. aquaticum as a form of biocontrol might be unpredictable at best. pb 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95, 666-676.
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Relocations of species have become a tool widely used in nature conservation, but insects have rarely been considered as targets. Here, we present a translocation project of the field cricket (Gryllus campestris L. 1758), which is...
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Relocations of species have become a tool widely used in nature conservation, but insects have rarely been considered as targets. Here, we present a translocation project of the field cricket (Gryllus campestris L. 1758), which is a threatened species at the northern edge of its range. Only ten populations were left in Lower Saxony (Germany), illustrating the need for urgent conservation measures. After 10 years of monitoring and management of an isolated population, 213 nymphs were captured and released at another nature reserve in summer 2001. The size of the new population increased significantly from 27 singing males in spring 2002 to 335 singing males in spring 2005. The occupied area increased from 5.66 ha to 33.14 ha. Altogether, the translocation project was evaluated as successful, but the inland dune proved to be not as suitable for the species as initially expected. Our results indicate that translocations of highly reproductive insect species are promising, as long as the release locality contains sufficiently large areas of suitable habitat and a high number of wild juveniles from a closely located and large source population are released in a climatically favorable period. Management and restoration of habitats, as well as continuous monitoring are of crucial importance for the success of the translocation project. Moreover, the importance of a high quality of cooperation between conservationists, authorities, foresters, farmers, financiers and scientists cannot be overstated.
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The presence of spermatozoa in vesicles in the cytoplasm of the epithelial cells that constitute the spermathecal wall of Melipona bicolor queen (Meliponini) is discussed in relation to the organ structure. The epithelial wall is ...
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The presence of spermatozoa in vesicles in the cytoplasm of the epithelial cells that constitute the spermathecal wall of Melipona bicolor queen (Meliponini) is discussed in relation to the organ structure. The epithelial wall is lined by an apparently continuous cuticle in the luminal surface that should be a non-transposable barrier to the luminal spermatozoa. However, some spermatozoa were seen crossing the cuticle through interruptions that was first interpreted as sectioning defects. Nevertheless, the sperm cells in well-structured cytoplasmic vesicles, bound by membranes and sometimes associated to multivesicular bodies, as well as cytoplasmic structures representative of intracellular digestion and the occurrence of the phenomenon in two of the three spermathecae studied, suggest a real spermiophagic hole in the spermathecal epithelial cells.
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Проанализированы трофические связи саранчовых, населяющих полупустыни и пустыни Нижнего Поволжья. Большая часть рассмотрен...
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Проанализированы трофические связи саранчовых, населяющих полупустыни и пустыни Нижнего Поволжья. Большая часть рассмотренных видов являются узкими олигофагами и монофагами. Они образуют четыре комплекса видов, которые трофически связаны с эдифика-торами наиболее широкораспространенных растительных сообществ в полупустыне (гигро- и мезофитные злаки, ксерофитные злаки, полыни и маревые). Показано, что трофическая специализация в значительной степени определяет особенности биотопической приуроченности и структуры сообществ саранчовых. Ил.3.
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Amplitude-temporal patterns of acoustic signals of Asiotmethis muricatus (Pall.), A. zacharjini(B.-Bien.),Dericorys tibialis (Pall.), Truxalis eximia Eich., Ochrilidia hebetata kazaka (Tarb.), Mecostethus alliaceus (Germ.) and Hya...
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Amplitude-temporal patterns of acoustic signals of Asiotmethis muricatus (Pall.), A. zacharjini(B.-Bien.),Dericorys tibialis (Pall.), Truxalis eximia Eich., Ochrilidia hebetata kazaka (Tarb.), Mecostethus alliaceus (Germ.) and Hyalorrhipis clausi (Kitt.) and also acoustic repertoires of Stenobothrm eurasius hyalosuperficies Vor. и Chorthippus macrocerm purpuratus Vor. are described for the first time. Acoustic signals of Stenobothrus fischeri (Ev.), Chorthippus maritimm Mistsh., Ch. mollis (Ch.), Ch. parallelus (Zett.), Ch. dichrous (Ev.), Ch. karelini^Uv.), Euchorthippus pulvinatus (F.-W.), Stethophyma grossum (L.), Aiolopus thalassinus (F.) and Bryodema gebleri (F.-W.) from before nonstudied populations are described. Some features of acoustic and sexual behaviour of Oedaleus decorus (Germ.), Oedipoda caerulescens (L.), Sphingonotus rubescens (Walk.) and, some other species are noted. A comparative analysis of the acoustic and sexual behaviour of studied species of grasshoppers was performed.
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A comparative study of male and female genitalia was carried out in thirty-seven Libyan species representing twenty genera of the family Acrididae. An attempt has been made to describe and illustrate the different structures, name...
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A comparative study of male and female genitalia was carried out in thirty-seven Libyan species representing twenty genera of the family Acrididae. An attempt has been made to describe and illustrate the different structures, namely, epiphallus, aedeagus, subgenital plate, supra-anal plate and cerci of the male, and spermatheca, ovipositor, subgenital plate, supra-anal plate and cerci of the female, in Acridids, with an aim to discover their significance in order to make the identification of genera and species, together with other generic characters, more perfect and convenient. Distinct family characters are shield or bridge-shaped condition of epiphallus; presence or absence of dorso-lateral appendices, oval sclerites and lophi on epiphallus; divided, undivided or flexured condition of aedeagus; presence or absence of gonopore process on aedeagus; condition of apical and pre-apical diverticula of spermatheca; presence or absence of glandular pouches of Cornstock and Kellog on female subgenitalplate; and rudimentary or well developed condition of egg-guide. Stable characters for separating the subfamilies are taken to be presence or absence of ancorae on epiphallus, long or short condition of aedeagal sclerites; elongate, slender or short andbroad condition of ovipositor valves: presence or absence of Jannone's organs and setae on posterior margin of female subgenital plate; and shape of diverticula of spermatheca. Useful generic characters are shape of male subgenital plate, supra-anal plate and cerci, broad or narrow condition of bridge, presence or absence of branch of bridge connecting lophi with bridge of epiphallus; mono-, bi- or tri-lobate condition of lophi of epiphallus, length and upcurved or downcurved condition of apical valveof aedeagus, shape of posterior margin of female subgenital plate, presence of setae on the whole posterior margin or confined to lateral margins only; and toothed, tuberculate or smooth condition of ovipositor valves, length of the lateral apodeme in relation to the dorsal valves. Specific characters are shape of egg-guide of female subgenital plate, shape of ovipositor valves and apical tips, shape of male supra-anal plate and cerci, size of anterior and posterior lobes of lophi of epiphallus, size and shape of ancorae, shape of apical valves of aedeagus; and size of apical and pre-apical diverticula and presence of protuberance on pre-apical diverticulum.
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Three agraeciine species are described from the north-eastern tropics of coastal Queensland. Two species of Austrosalomona are described. A. destructor sp. nov. is common from the Daintree region to Cairns where it has been seen t...
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Three agraeciine species are described from the north-eastern tropics of coastal Queensland. Two species of Austrosalomona are described. A. destructor sp. nov. is common from the Daintree region to Cairns where it has been seen to destroy orchids and other garden flowers. A. poecila has been found on coastal islands as well as at a few localities on the mainland north of Cairns. It has not been implicated in any destructive activities. Salomona nori sp. nov. is known from Kutini-Payamu (Iron Range) where it has been found living in tree holes. It is a large and formidable species that attracts the attention of tourists. Karyotypes and acoustic information are presented for all three species.
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