Search results for "Larva"

Monitoring of Bacillus Thuringiensis Cry3Aa Toxin Pore Formation using Artificial Bilayer Array with Fused Brush Border Membrane Vesicles from Colora…

2017

Cynipid wasps inducing galls on plants of the genus Picris (Asteraceae) in Europe, with a description of a new species of Phanacis Foerster (Hymenopt…

2008

13 paginas y 8 figuras

The Oral Cavities of Central European Anuran Larvae (Amphibia)

1982

AbstractWith few additions (structures here called prenarial lobes, prenarial arena pustulations, prevalar pustulations), WASSERSUG'S ( 1976) terminology is adequate to describe the oral structures of Central European anuran larvae. The oral cavities of Bombina and Alytes (Discoglossidoidei) are very similar in structure. Based on oral anatomy Pelabates fuscus appears to occupy an intermediate position within the Anura and a basal position among the Ranoidea, which are morphilogical very heterogeneous in oral characters. This assessment is consistent with the findings of other authors working on the anatomy of the tadpole head. Extensive morphological diversity can be found even within the …

Growth and survival of European whitefish larvae under enhanced UV-B irradiance

2004

Two laboratory rearing experiments with newly hatched European whitefish Coregonus lavaretus larvae were performed to study the effects of UV-B (280–315 nm) radiation on their survival and growth. The results indicate that under normal circumstances in Finnish lakes, enhanced UV irradiance will not be a threat to the survival of newly hatched European whitefish larvae.

Cuticle: Formation, Moulting and Control

1984

The relative rigidity of the arthropod exoskeleton makes it impossible for body size to increase continuously during the postembryonic development of these animals. Once they have hatched from the egg, they grow in steps, passing through a variable number of (larval) stages (Fig. 1 a). Apart from a few exceptions, there are between 3 and 10 such stages in the arachnids, 3–20 in the crustaceans, and 3–10 in the insects. In many cases a metamorphosis stage intervenes (some crustaceans; holometabolous insects) (Fig. 9b, c).

Interspecific associations among larval helminths in fish

2001

Various processes can generate associations between the larvae of different helminth species in their fish intermediate or paratenic host. We investigated the pairwise associations among larval helminth species in eight different fish populations, using two different coefficients of associations, in order to determine in what situations they are strongest. All helminth species included use the fish studied as either their second intermediate host or their paratenic host, and are acquired by the fish when it ingests an infected first intermediate host. The intensity of infection correlated positively with fish length for most helminth species. Pairs of species which both exhibited positive c…

Effects of UV radiation on the vertical distribution of vendace [Coregonus albula (L.)] larvae in Finnish lakes

2005

– Positively phototactic vendace larvae may be vulnerable to enhanced springtime UV levels unless they are able to avoid them. Experimental results, however, suggested that UV avoidance can exist. In this study field data from eight Finnish lakes with different characteristics were analysed. The aim of the study was to determine whether vendace larvae stayed deeper in the water column during sunny than during cloudy periods because thick cloud cover considerably reduces UV irradiance. In addition, avoidance behaviour of larvae was studied in acrylic tubes placed in a lake and under laboratory conditions. The avoidance of high UV-B exposure existed both in the littoral and pelagic zone of th…

Cold tolerance during larval development: effects on the thermal distribution limits of Leptinotarsa decemlineata

2009

Insects' cold tolerance during their development is a surprisingly understudied subject in ecology, despite the fact that subzero temperatures during the growing season are common at high altitudes and latitudes. Subzero temperatures can have detrimental effects on organisms, restricting a species' range. This study addresses the question whether night frosts during the growing season have an instant or delayed negative impact on larval mortality of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). We also tested whether populations from the centre (Poland) and margins (Russia) of the distribution range of L. decemlineata differ in their responses to s…

Factors affecting abundance of Triaenophorus infection in Cyclops strenuus, and parasite-induced changes in host fitness.

2000

Factors affecting the abundance of Triaenophorus crassus and Triaenophorus nodulosus procercoids in their copepod first intermediate host, Cyclops strenuus, and effects of infection on feeding behaviour, reproduction and survival of the host were studied experimentally. When exposed to the same number of coracidia, copepods harboured considerably less procercoids in the trials where ciliates or Artemia salina nauplii were given as alternative food items. The prevalence of infection was higher in adult copepods as compared with copepodite stage IV and stage V, and higher in stage V than in stage IV. The prevalences in adult females and males did not differ significantly from each other. The …

Drought-induced positive feedback in xylophagous insects: Easier invasion of Scots pine leading to greater investment in immunity of emerging individ…

2012

Abstract We studied the infestation rate of Scots pine Pinus sylvestris by xylophagous insects in relation to distance from forest lakes in eastern Latvia, northern Europe. In summers of 2008 and 2009, we felled 72 pines of approximately 65 years age. Sections of the logs were incubated in insect emergence traps. The trees located near lakes were significantly less infested by xylophagous insects than those sampled at greater distances from the lakes. We also tested the ability of Tomicus piniperda , the most abundant species of xylophagous insects in our samples, to resist the entomopathogenic fungus Beauveria bassiana . The results show that beetles captured near lakes were more susceptib…