Food Preference Of Larvae Research Articles

Does Singular and Stacked Corn Affect Choice Behavior for Oviposition and Feed in Spodoptera frugiperda (Lepidoptera: Noctuidae)?

Little is known about the effects of genetically modified corn plants on the foraging of Spodoptera frugiperda (J.E. Smith). Therefore, this study examines whether singular herbicide-tolerant and insect-resistant plants and their stacked events interfere with food preference and oviposition of S. frugiperda. Two non-Bt corn hybrids and three Bt-hybrids, some of them with glyphosate tolerance (GT), were evaluated. Food preference of larvae and biological parameters were assessed. Oviposition preference bioassays involved choice and no choice condition in plants uninfested and previously infested by larvae in a greenhouse and in the field. The results indicate that there is no relationship between preference of larvae and adult moths. Adult females selected preferentially transgenic hybrids, while larvae selected non-Bt hybrid. Fall armyworm larvae avoid Bt-toxin-expressing leaf tissues, survived only on the non-Bt leaf tissues, and showed minor differences in other life-history traits reared on GT and non-transgenic corn leaf tissues. Female moths showed preference for transgenic plants to lay eggs, but with variable output between previously infested and uninfested plants with larvae. The fact that moths preferred Ag 3700RR2 and non-Bt hybrids for oviposition supports the refuge's strategy aiming at producing susceptible individuals. The use of this hybrid must be integrated with a program of control. The results showed also the importance of correct hybrid selection as part of insect resistance management to Bt-plants. The implications of these findings for understanding the impacts of plant-mediated cues on pest behavior in transgenic crop systems are discussed.

Effect of trophic conditions on the growth and abundance of larvae of herring Clupea pallasii marisalbi in areas of their mass aggregations in Kandalaksha and Onega bays of the White Sea

On the basis of materials collected during June 18–26, 2012, in three polygons in Onega (Ukhta Inlet) and Kandalaksha (Chupa and Knyazhaya inlets) bays of the White Sea, the effect of concentration and size-species structure of the zooplankton and of the amount of potential predators on the numbers and growth rate of larvae of the White Sea herring Clupea pallasii marisalbi are considered. The total numbers of zooplankton in Ukhta, Chupa, and Knyazhaya inlets (25041, 39162–76555, and 18459–33870 ind/m3, respectively) noticeably exceeds minimal values necessary for the growth and development of larvae. Correlation analysis of the size composition of larval herring and size-species composition of net mesoplankton indicates that food preferences of larvae of different size groups significantly differ. The growth rate of larvae in Kandalaksha Bay is 0.20–0.25 mm/day. A feedback between the numbers of larvae of the White Sea herring and hydromedusas was revealed: in Chupa Inlet at a greater concentration of jelly-bodied zooplankton, the numbers of larvae were considerably lower, and their reduction at 5 days turned out to be more significant than at a relatively low concentration of medusas in Knyazhaya Inlet. This indicates that food conditions are not always a single and decisive factor responsible for the formation of strong or weak-year classes of herring.

Larval and adult food preferences of the poinsettia thrips Echinothrips americanus Morgan, 1913 (Thysanoptera: Thripidae)

Numerous occurrence of Echinothrips americanus Morgan, 1913, a relatively newly established pest in European greenhouses, on a wide spectrum of cultivated plants throughout Slovakia has encouraged us to present current data on its food ecology. Analysing 1,650 plant species, the poinsettia thrips was found on 106 species (48 families) including 19 showing sporadic, 75 moderate and 17 high infestation. Larvae were detected on 25 plant taxa from 13 families, most of them being new hosts. Mature clusters of Acalypha hispida, showing moderate to high infestation level and carrying both larvae and adults, were selected for more detailed statistical evaluation. Preference of adults for upper and lower leaf surface tends to be without statistical significance, the larvae on the contrary were strongly related to the lower side (Pearson’s χ2 = 13.3552, P = 0.0013). Concerning the age, increased occurrence was apparent on younger leaves for both larvae and adults. For larvae the nonparametric test gives the statistical difference between three age categories of leaves with the following values: Kruskal–Wallis χ2 = 6.6384, P = 0.03618. The statistical significance of age seems to be more crucial for younger shoots, as proved by the statistics for both larvae (Kruskal–Wallis χ2 = 8.4852, P = 0.0144) and adults (Kruskal–Wallis χ2 = 7.1049, P = 0.0287). Different food preferences of larvae and adults may result in specific approach when applying an effective biological or chemical control. Narrower tolerance of larvae could make them more manageable target in plant protection instead of efforts to control the whole thrips population.

Food preference and performance of the larvae of a specialist herbivore: variation among and within host-plant populations

Specialist herbivores are suggested to be unaffected by or attracted to the defense compounds of their host-plants, and can even prefer higher levels of certain chemicals. Abrostola asclepiadis is a specialist herbivore whose larvae feed on the leaves of Vincetoxicum hirundi- naria, which contains toxic alkaloids and is unpalatable to most generalist herbivores. The food choice, leaf consumption and growth of A. asclepiadis larvae were studied to determine whether there is variation among and within host-plant populations in their suitability for this specialist herbivore. There was significant variation in food preference and leaf consumption among host-plant populations, but no differences were found in larval growth and feeding on different host-plant populations.A. asclepiadis larvae preferred host-plant populations with higher alkaloid concentrations, but did not consume more leaf material from plants originating from such populations in a no-choice experiment. There was also some variation in food preference of larvae among host-plant individuals belonging to the same population, suggesting that there was variability in leaf chemistry also within populations. Such variation in larval preference among host-plant genotypes and popula- tions may create potential for coevolutionary dynamics in a spatial mosaic. © 2005 Elsevier SAS. All rights reserved.

Prey preference and feeding capacity of the larvae ofAblattaria arenaria [Coleoptera: Silphidae], a snail predator

The larval stages ofAblattaria arenaria were provided with 4 different snail species:Monacha syriaca (Ehrenberg),Xeropicta derbentina (Krynicki),Candidula sp., andZebrina eburnea (Pfeiffer) to determine if the prey species affected developmental time and food preference of larvae. Functional response of each larval stage ofA. arenaria was also tested for increasing density ofX. derbentina, the most common prey species found in association withA. arenaria locally.