Patterns Of Host Plant Use Research Articles

Host plant use among closely related Anaea butterfly species (Lepidoptera, Nymphalidae, Charaxinae).

There is a great number of Charaxinae (Lepidoptera: Nymphalidae) species in the tropics whose larvae feed on several plant families. However the genus Anaea is almost always associated with Croton species (Euphorbiaceae). This work describes patterns of host plant use by immature and adult abundance on different vertical strata of sympatric Anaea species in a forest of Southeastern Brazil. Quantitative samples of leaves were taken in April/1999 and May/2000 to collect eggs and larvae of four Anaea species on C. alchorneicarpus, C. floribundus and C. salutaris in a semideciduous forest. Sampled leaves were divided into three classes of plant phenological stage: saplings, shrubs and trees. The results showed that the butterfly species are segregating in host plant use on two scales: host plant species and plant phenological stages. C. alchorneicarpus was used by only one Anaea species, whereas C. floribundus was used by three species and C. salutaris by four Anaea species. There was one Anaea species concentrated on sapling, another on sapling/shrub and two others on shrub/tree leaves. Adults of Anaea were more frequent at canopy traps but there were no differences among species caught in traps at different vertical positions. This work supplements early studies on host plant use among Charaxinae species and it describes how a guild of closely related butterfly species may be organized in a complex tropical habitat.

Larval Case Architecture and Implications of Host‐Plant Associations for North AmericanColeophora(Lepidoptera; Coleophoridae)1

The case‐bearing moths of North America are represented by a single genus,Coleophora, which contains approximately 144 described species. All are external seed or leaf miners that inhabit portable silk cases during most of the larval stage. Architectural and ecological characters from larval cases were used in cladistic analysis to investigate existing case groups for 32 North American species ofColeophora. Cladistic analysis confirmed monophyly of certain case groups, but not of others. Host‐plant preferences were also examined. The pattern of host plant use reflects more closely preference for certain plant tissues (seeds versus leaves) and growth forms (herbaceous versus woody) with exploitation of different plant taxa, rather than preference for certain plant taxa with exploitation of different plant tissues.

Larval Case Architecture and Implications of Host-Plant Associations for North American Coleophora (Lepidoptera; Coleophoridae)

The case-bearing moths of North America are represented by a single genus, Coleophora, which contains approximately 144 described species. All are external seed or leaf miners that inhabit portable silk cases during most of the larval stage. Architectural and ecological characters from larval cases were used in cladistic analysis to investigate existing case groups for 32 North American species of Coleophora. Cladistic analysis confirmed monophyly of certain case groups, but not of others. Host-plant preferences were also examined. The pattern of host plant use reflects more closely preference for certain plant tissues (seeds versus leaves) and growth forms (herbaceous versus woody) with exploitation of different plant taxa, rather than preference for certain plant taxa with exploitation of different plant tissues.

Host plant specificity in several species of generalist mite predators

Summary1. Species in the genus Neoseiulus are considered to be generalist predators, with some species used in biological control programmes against phytophagous mites and insects.2. A general survey of Neoseiulus species in inland Australia indicated that different species are associated with particular tree species. This pattern of host plant use was investigated for four Neoseiulus species (N. buxeus, N. cappari, N. brigarinus, N. eremitus) by means of a sampling programme through time and across space.3. Each species of Neoseiulus was collected entirely or mostly from one species of tree; little or no overlap was detected despite the tree species growing in well‐mixed stands. Host plant specificity thus appears to be strong in this genus.4. Species in two other genera (Pholaseius and Australiseiulus), also considered to be predatory, showed a similar association with particular tree species.5. The implications for the use of these predators in biological control are considerable. In particular, phytoseiid species with specific needs in terms of host plants may not be suitable for use as general purpose predators. Meeting the needs of phytoseiids through the modification of host plant attributes may be a step towards enhancing their efficacy as biological control agents.

How foraging tactics determine host-plant use by a polyphagous caterpillar.

The use of multiple host-plant species by populations of insect herbivores can result from a variety of possible ecological and behavioral mechanisms. An understanding of the foraging mechanisms determining polyphagy in relation to local ecological conditions is therefore essential to understanding the evolutionary ecology of polyphagy. Here, we evaluate patterns of host-plant use by the polyphagous caterpillar Grammia geneura (Lepidoptera: Arctiidae) in relation to host-plant availability and foraging tactics of individuals. Field surveys of caterpillar feeding and plant abundance carried out across several sites, seasons, and years showed that: (1) G. geneura consistently preferred forbs to grasses and woody plants, (2) forb-feeding was opportunistic, supporting the idea that caterpillars sample locally available host-plants, and (3) there were consistent patterns of host-plant use that were not explained by host-plant availability (electivity). An independent set of 7-h observations of 11 caterpillars showed that electivity for a subset of caterpillar-host associations could be explained by variation in the probability of initiating feeding and the average duration of feeding bouts on different hosts but not by variation in the probability of encountering different hosts, thus providing a behavioral basis for the observed variation in host-plant use. The use of detailed foraging tactics by larvae to explain host-plant use at the population level is a novel contribution of this study.

Gut physicochemistry of grassland grasshoppers

We examined the pH and Eh of the digestive tract of 23 species of mixed-grass prairie grasshoppers, and asked whether these traits were associated with the species breadth and forb composition of their diets. We report that the gut lumen of all grasshoppers was oxidizing and ranged from slightly acid to neutral depending on the gut region and species. Although gut physicochemical conditions differed among species, the differences were of small magnitude. Conditions were fairly uniform along the digestive tract, which suggests little or no regulation of pH or Eh. Gut conditions were independent of diet breadth and the percentage of forbs in the diet. These results suggest that physicochemical conditions of grasshopper guts are not highly regulated and are not influenced by their most recent meal or by broad scale patterns of host-plant use.

Host species and plant part specificity of the polyphagous onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), in an Australian cotton‐growing area

We determined the pattern of host plant use of Thrips tabaci by surveying wheat and five weed species growing near cotton crops in the area centred on the Namoi Valley, northern New South Wales. Highest densities of T. tabaci females and larvae were found on inflorescences and vegetative parts of turnip weed, Rapistrum rugosum, and lowest on wheat, Triticum aestivum. The other plant species (Paterson’s curse, Echium plantagineum, curled dock, Rumex crispus, Mayne’s pest, Verbena tenuisecta and sowthistle, Sonchus oleraceus) hosted intermediate densities of T. tabaci. The presence of high densities of reproductive T. tabaci on flowering and vegetative parts of turnip weed suggests that this species is a primary host of T. tabaci in the study area.

Host species and plant part specificity of the polyphagous onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), in an Australian cottongrowing area

AbstractWe determined the pattern of host plant use of Thrips tabaci by surveying wheat and five weed species growing near cotton crops in the area centred on the Namoi Valley, northern New South Wales. Highest densities of T. tabaci females and larvae were found on inflorescences and vegetative parts of turnip weed, Rapistrum rugosum, and lowest on wheat, Triticum aestivum. the other plant species (Paterson's curse, Echium plantagineum, curled dock, Rumex crispus, Mayne's pest, Verbena tenuisecta and sowthistle, Sonchus oleraceus) hosted intermediate densities of T. tabaci. the presence of high densities of reproductive T. tabaci on flowering and vegetative parts of turnip weed suggests that this species is a primary host of T. tabaci in the study area.

Variable chemical defence in the checkerspot butterfly Euphydryas gillettii (Lepidoptera: NymphaIidae)

Abstract. Like other checkerspots, Euphydryas gillettii butterflies may contain the defensive chemicals, iridoid glycosides, which are sequestered from their hostplants during larval feeding. We analysed the iridoid glycoside content of E.gillettii adults from two different populations, Warm Lake, Idaho, and Granite Creek, Wyoming, that have different patterns of hostplant use. Gas chromatographic analysis of thirty butterflies from the Wyoming population showed that they contained a mean of 1.27 (±0.19 SE) % dry weight iridoid glycosides. Notably, 20% of these butterflies contained no detectable iridoid glycosides. In contrast, nineteen butterflies from the Idaho population contained a mean of 3.89 (±0.38 SE) % dry weight iridoid glycosides, and all butterflies contained iridoid glycosides. These results illustrate how the chemical defence of herbivorous insects varies according to differential use of potential hostplants.

Host-plant selection by phytophagous insects

Preface. Acknowledgements. Introduction. 1. Patterns of host-plant use. 2. Chemicals in plants. 3. Sensory systems. 4. Behavior: the process of host-plant selection. 5. Behavior: the impact of ecology and physiology. 6. Effects of experience. 7. Genetic variation in host selection. 8. Evolution of host range. Glossary. Taxonomic index. Subject index.

Ecological and taxonomic trends in macrolepidopteran host plant selection

Patterns of host plant use by larvae of macrolepidoptera feeding on trees and shrubs in Britain and Canada are examined. The incidence of polyphagous species varies among different lepidopteran taxa. Among largely monophagous taxa host plant switching has often occurred. The greater similarity of insect faunas on closely related plants is documented using cluster analysis. The Canadian data reveal that lepidopterans feeding on conifers are less specific in their host plant choice than species feeding on angiosperms. The numerical analyses also provide evidence of greater overlap in the insect faunas of plants belonging to the same ecological association. These results are discussed with particular reference to Lepidoptera-plant coevolution.

RESOURCE PARTITIONING IN PASSION VINE BUTTERFLIES.

The use of phytophagous insect communities as model systems to elucidate ecoevolutionary processes, although encountering considerable success in some areas (Southwood, 1960, 1961; Opler, 1974; Strong, 1974a,b), has not been actively extended to include competitive phenomena. The partitioning of food resources has been well documented in many animal groups, especially vertebrate predators (Schoener, 1974); however, the few studies made to date have not presented convincing evidence that such patterns are typical for any group of invertebrate herbivores. Several possible cases of competition related resource partitioning between pairs of lepidopteran species have been reported by Gilbert and Singer (1976) from an extensive examination of the lepidopteran literature, and Shapiro and Carde (1970) suggested that host plant and habitat separation among three species of satyrine butterflies may be explicable in terms of competition induced ecological shifts. On a larger scale Owen (1972) noted that the patterns of host plant use in West African acraeine butterflies are consistent with resource partitioning. On the other hand, very few studies have specifically examined the dynamics of resource use as related to competition. Colwell (1973) has presented a convincing picture of the ecological dynamics accounting for host plant separation of two potentially competing nectivorous mites. However, the only study to date specifically designed to identify partitioning within an insect herbivore guild failed to reveal clearcut patterns among temperate stem-borers (Rathcke, 1976). Moreover, theoretical arguments have been put forward to suggest that unambiguous patterns of resource partitioning are not generally to be expected in invertebrate herbivores, and May (1973:166) goes even farther in stating that . many insect communities, and many plant communities, have complex multidimensional niche structure involving, inter alia, a variety of chemical dimensions. In addition predation and other interactions beyond simple competition are pervasive in these invertebrate and plant communities. Such situations are best avoided for the time being. I present here evidence that at least one group of insect herbivores corresponds in many details to predictions derivable from competition and foraging theory and discuss some of the more important details and extensions of these predictions.