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12. Response of the reduviid bug, Rhynocoris marginatus (Heteroptera: Reduviidae) to six different species of cotton pests
- Creator:
- Sahayaraj, kitherian, Muthu Kumar, Subramanian, and Enkegaard, Annie
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, ploštice, zákeřnicovití, Heteroptera, Reduviidae, Rhynocoris marginatus, macromolecular profiles, kairomone, feeding behaviour, haemocyte levels, 2, and 59
- Language:
- English
- Description:
- In Indian agro-ecosystems Rhynocoris marginatus (F.) is one of the most abundant predatory arthropods and feeds on a wide range of insect pests. We investigated the responses of R. marginatus to six species of cotton pests: Spodoptera litura (F.), Sylepta derogata (F.), Pericallia ricini (F.), Mylabris indica (Thunberg), Mylabris pustulata (Thunberg) and Dysdercus cingulatus (F.), in terms of its predatory behaviour (approach and handling times), weight gain, macromolecular profile (content of carbohydrates, proteins, free aminoacids and lipids) and haemocytic profile. We also determined the predator's reliance on kairomones from different species of prey. Larvae of the species of Lepidoptera studied were approached and captured more quickly than adults of the two meloid coleopteran and one heteropteran pest and were more beneficial to the predator in terms of weight gain. Predators had a higher total protein content when reared on larvae of the three lepidopteran species, higher lipid content when reared on adults of the two meloid coleopteran species and a higher carbohydrate content when reared on adults of one heteropteran species. The number of haemocytes was greater in predators reared on larvae of the Lepidoptera studied, followed by those reared on adults of the heteropteran and lowest in those reared on adults of the two meloid coleopterans. Response to kairomones was strongest for S. litura followed by S. derogata and M. pustulata. We conclude that the Lepidoptera studied tended to be, for this predator, superior prey, with S. litura being especially beneficial and the prey species for which R. marginatus has the highest kairomonal preference. Moreover, we propose that R. marginatus may be useful as a biocontrol agent against lepidopteran cotton pests., Kitherian Sahayaraj, Subramanian Muthu Kumar, Annie Enkegaard., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
13. Seasonal use of ponds as foraging habitat by Eurasian otter with description of an alternative handling technique for common toad predation
- Creator:
- Almeida, David, Rodolfo, Nahuel, Sayer, Carl D., and Copp, Gordon H.
- Type:
- article, model:article, and TEXT
- Subject:
- amphibians, Bufo bufo, feeding behaviour, pond biodiversity, and spraint analysis
- Language:
- English
- Description:
- Research in freshwater ecology has traditionally focused on water courses or large still waters. However, ponds support proportionately high levels of biodiversity relative to other inland waters in Europe, and foraging by Eurasian otter Lutra lutra (L., 1758) could have considerable impacts on species composition in these small water bodies. The aim of the present study was to analyse otter spraints around ponds during two contrasting seasons (winter and spring) in north Norfolk (eastern England), where both otter and ponds are of particular conservation concern. Spraint density, prey diversity and the consumption of river-associated species were higher in spring than winter. In both seasons, birds were the most important prey category as ingested biomass. European eel Anguilla anguilla (L., 1758) and amphibians, specifically common frog Rana temporaria L., 1758 and common toad Bufo bufo (L., 1758), were more consumed in spring, whereas northern pike Esox lucius L., 1758 and tench Tinca tinca (L., 1758) were taken in winter. Non-native common carp Cyprinus carpio L., 1758 was important in both seasons, whereas threatened native crucian carp Carassius carassius (L., 1758) was a minor prey item. Massive kills of common toad, which involved a new handling technique for predation on this species, were observed mainly in spring. The study demonstrated otters to display great plasticity in foraging behaviour and contributes to the understanding of otter predatory pressure on pond biodiversity, with implications for landscape management.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14. Seed preferences of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae): Are there specialized trophic populations?
- Creator:
- Kristenová, Marta, Alice Exnerová, and Pavel Štys
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, entomologie, Heteroptera, Pyrrhocoridae, Pyrrhocoris apterus, feeding duration, feeding behaviour, trophic population, seed preferences, Tilia platyphyllos, Althaea officinalis, Robinia pseudacacia, 2, and 59
- Language:
- English
- Description:
- The populations of the firebug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae) in Europe exhibit three kinds of host plant associations: feeding on seeds of (1) Tilia spp. (Tiliaceae), (2) Malvaceae (s. str.), and (3) Robinia pseudacacia (Fabaceae). The three host plant taxa often grow in different habitats and localities. We have tested the hypothesis that P. apterus forms on different host plants specialised "trophic populations" which also influence its food preference. We have collected P. apterus from localities with Tilia platyphyllos, Malva neglecta or Robinia pseudacacia as host plants and tested their preferences in a multiple choice test involving seeds of Tilia cordata, T. platyphyllos, Althaea officinalis, Alcea rosea and Robinia pseudacacia. The original host plant of P. apterus population had no influence on food preferences. However, the preferences differed between adults and the third instar larvae. The adults preferred seeds of Robinia pseudacacia followed by Althaea officinalis, while the preferences of larvae were less pronounced and ranked in order Althaea officinalis, Robinia pseudacacia, and Tilia platyphyllos. Existence of trophic populations of P. apterus was not confirmed by our experiment. Durations of feeding were longer on preferred species of seeds in both adults and larvae. and Marta Kristenová, Alice Exnerová, Pavel Štys.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
15. Self-sustaining infrapopulation or colony? Redial clonal groups of Himasthla elongata (Mehlis, 1831) (Trematoda: Echinostomatidae) in Littorina littorea (Linnaeus) (Gastropoda: Littorinidae) do not support the concept of eusocial colonies in trematodes
- Creator:
- Kirill Vladimirovič Galaktionov, Podvyaznaya, Irina M, Nikolaev, Kirill E, and Levakin, Ivan A
- Format:
- print, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- kasty, rozmnožování (biologie), castes, reproduction, rediae, parthenitae, Digenea, eusociality, germinal mass, allometry, developmental arrest, feeding behaviour, 2, and 59
- Language:
- English
- Description:
- Trematode sporocysts and rediae reproduce by parthenogenesis, forming clonal groups in the molluscan host. It has recently become popular to consider these groups as eusocial colonies, with division of labour between rediae morphs: small 'soldiers' incapable of reproduction defend the colony, while large rediae reproduce. Alternatively, clonal groups can be considered as self-sustaining infrapopulations. We tested these two hypotheses in the light of new data on rediae of Himasthla elongata (Mehlis, 1831) from snails Littorina littorea (Linnaeus) concerning ultrastructure, growth character and composition of their groups. Clonal groups under study contained rediae of different age and maturity stages: small (young) rediae, rediae with early cercarial embryos, rediae with late embryonic cercariae, rediae with fully formed motile cercariae, rediae with redial embryos and degenerating rediae. Small rediae had a reproductive organ, the germinal mass, whereas most large rediae with developing cercariae did not, which contradicts the eusocialconcept. Overall distribution of rediae by size and by gut to body length ratio was bimodal, which agrees with the eusocial concept ('soldiers' and 'reproductives' as modal size classes). On closer inspection, however, the bimodal size-frequency distributions (SFD) turned out to be the sum of unimodal SFD of rediae at various stages of maturity. The overall bimodality was determined by the character of redial growth resulting in a relatively low occurrence of intermediate morphs and by the developmental arrest in young rediae. The facts that small rediae can attack other rediae and concentrate in the anterior parts of the mollusc can be explained by age-related feeding preferences and niche segregation. They are unlikely to be associated with the 'colony' defence against invaders. To sum up, clonal groups of H. elongata rediae in our study represented self-sustaining infrapopulations., Kirill V. Galaktionov, Irina M. Podvyaznaya, Kirill E. Nikolaev, Ivan A. Levakin., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public