Aphid

About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.

Biodiversity consequences of predation and host plant hybridization on an aphid-ant mutualism

Abstract: We examined the hypothesis that mutualists, predators, and host plant quality act in concert to determine the distribution and abundance of a common herbivore. The aphid, Chaitophorus populicola, is found only in association with ants, which provide tending services and protection from predators. As a consequence, aphid abundance declined by 88% on host plants located ?6 m from an ant mound. Differences in host plant quality resulted in aphid fecundity being greatest on narrowleaf cottonwoods, 7-22% less on back- cross hybrids, 37-46% less on F1 hybrids, and 57-61% less on Fremont cottonwoods. Due to the combined effects of these factors, we found that the realized aphid habitat was only 21% of their potential habitat. On trees where aphids and tending ants are present, aphids and ants greatly outnumber any other arthropod species; therefore, we examined the hypothesis that the factors affecting aphid density and distribution are also determinants of arthropod community structure. On a per-tree basis, observational data showed that arthropod species richness was 51% greater and abundance was 67% greater on trees where aphid-ant mutualists were absent relative to trees where they were present. When aphids were experimentally removed and ants abandoned the tree, we found the same pattern. On a per-tree basis, arthropod species richness increased by 57%, and abundance increased by 80% where aphid-ant mutualists were removed, relative to control trees. Overall, a total of 90 arthropod species were examined in this study: 56% were found only on trees without aphid-ant mutualists, 12% were found only on trees with aphid-ant mutualists, and 32% were common to both. Specific guilds were also affected; the aphid-ant mutualism had a negative effect on herbivores, generalist predators, and other species of tending ants, and a positive effect on specialist enemies of aphids. These results suggest that, by examining the factors responsible for the population dynamics of a common herbivore, we may also uncover mechanisms that de- termine arthropod community structure. Furthermore, studies that address the role of mu- tualism in shaping communities are underrepresented in the literature; these results em- phasize the importance of mutualism in ecological communities.

The relative importance of glucosinolates and amino acids to the development of two aphid pests Brevicoryne brassicae and Myzus persicae on wild and cultivated brassica species

Abstract: This paper describes an experiment to investigate the relative importance of glucosinolates and the availability of free amino acids in the phloem to the feeding behaviour and development of the specialist brassica aphid, Brevicoryne brassicae (L) (cabbage aphid) and the generalist, Myzus persicae, (Sultzer) (peach potato aphid). Aphid development was determined on brassica species and cultivated brassica varieties. Analysis of individual glucosinolates in the wild brassica species identified significant differences in their profiles and in their concentrations present in freeze dried leaves. Multiple regression analysis showed a significant correlation (r = 0.83) between the intrinsic rate of increase of B. brassicae and glucosinolate concentrations; four glucosinolates, 2-OH-3-butenyl, and 2-propenylglucosinolate, 3-methoxyindolyl and 4-pentenylglucosinolates accounted for 79% of the variation. The intrinsic rate of increase of M. persicae was less correlated, though still significant (r = 0.5); 3-indolyglucosinolate and 3-butenylglucosinolate accounted for 47% of the variation. Regression analysis also showed a correlation between phloem amino acid concentrations and the intrinsic rate of increase of B. brassicae (r = 0.48) but not of M. persicae. The concentration of the important amino acids tyrosine, alanine, leucine and glutamic acid, accounted for 43% of the variation in intrinsic rate of increase. Leaf water potential of the Brassica species showed no relationship with the intrinsic rate of increase of either B. brassicae or M. persicae.

Non-additive effects of multiple natural enemies on aphid populations.

Abstract: The question of whether multiple natural enemies often interact to produce lower host mortality than single enemies acting alone has not yet been resolved. We compared the effects of four different combinations of natural enemies-parasitoids, predators, parasitoids plus predators, and no enemies-on caged aphid populations on marsh elder, Iva frutescens, in west-central Florida. Using starting densities of natural enemies commonly found in the field, we showed that parasitoid wasps reduced aphid population densities more than predatory ladybird beetles. The addition of predators to cages containing parasites reduced the ability of parasitoids to decrease aphid population densities. Because the experiments ran only over the course of one generation, such a reduction in the effectiveness of parasites is likely caused by interference of predators with parasitoid behavior. Parasitism in the cages containing both parasitoids and predators was reduced when compared to percent parasitism in parasitoid-only cages, but this could also be due to predation. Our experiments showed that ladybird beetles prey on parasitized aphids. Thus over the long-term, the effectiveness of parasites is impaired by the interference of predators on ovipositing parasitoids and by the predation of parasitized aphids. The effects of natural enemies in this system are clearly non-additive.

Clonal variation and covariation in aphid resistance to parasitoids and a pathogen

Abstract: The potential rate of evolution of resistance to natural enemies depends on the genetic variation present in the population and any trade-offs between resistance and other components of fitness. We measured clonal variation and covariation in pea aphids (Acyrthosiphon pisum) for resistance to two parasitoid species (Aphidius ervi and A. eadyi) and a fungal pathogen (Erynia neoaphidis). We found significant clonal variation in resistance to all three natural enemies. We tested the hypothesis that there might be trade-offs (negative covariation) in defensive ability against different natural enemies, but found no evidence for this. All correlations in defensive ability were positive, that between the two parasitoid species significantly so. Defensive ability was not correlated with fecundity. A number of aphid clones were completely resistant to one parasitoid (A. eadyi), but a subset of these failed to reproduce subsequently. We discuss the factors that might maintain clonal variation in natural enemy resistance.

Biology and ecology of Aphis gossypii glover (Homoptera: Aphididae)

Abstract: Aphis gossypii Glover is a destructive pest of over two dozen crops world wide Damage to a few of these crops is due to direct feeding, but for most of these crops its impact is through its role as a virus vector As expected, this has resulted in many articles dealing with methods of controlling this insect The aphid has the ability to become resistant to many pesticides and there is growing concern over environmental impacts of pesticide use As a result, manipulation of the agroecosystem will play an ever increasing role in the management of this insect Most aspects of the biology of this aphid are covered in this review The recurrent theme centers around the importance of host plant influences on the biology of the aphid In addition to examining the literature on the biology of the aphid, a large section is devoted to organisms which influence mortality in the aphid, and to aphid borne viruses transmitted by this aphid This review covers the literature from 1912 to 1995, but articles on aphid management (eg pesticide efficacy, planting date) were omitted except where they deal with the aphid's biology or ecology Research on the biology of this aphid has been heavily skewed into several disparate categories First, research has focused on the influence of host plant and temperature on the reproductive rate of this aphid Second, research has focused on the cause for alate production such as nutritional stress, other nutritional factors, crowding, and temperature Third, research has focused on the viral borne pathogens transmitted by this aphid Three specific cases are highlighted: citrus tristeza, cucumber mosaic virus, and the potyviruses Last, research has focused on the role of organisms which feed on this aphid Due to the complexity of research possible in this area, very little research has explored the effect of these "beneficial organisms" on life history traits of this aphid