Host Feeding Preferences Research Articles

Indigenous Natural Enemies Associated with Phyllocnistis citrella (Lepidoptera: Gracillariidae) in Eastern Spain

Abstract The incidence of generalist indigenous natural enemies of the citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera; Gracillariidae), was monitored during three growing seasons at two different orchards located in the major citrus-growing area of Spain. Composition of the parasitoid complex changed during the study period. However, the eulophids Cirrospilus near lyncus Walker and Pnigalio pectinicornis L. were consistently the predominant species. Despite the varying composition of the parasitoid complex, oviposition, host feeding, and predatory preferences of the natural enemies of the CLM clearly centered on third instar larvae. Incidence of beneficial fauna increased as the season progressed, reaching maximal values up to 70% of susceptible leafminers (mature larvae) at the end of the summer. Parasitism was significantly related to relative host density. However, predation showed no relationship to host availability but did so to flushing in one of the orchards. Incidence of indigenous natural enemies of the CLM should not be ignored when planning any introduction of exotic parasitoids, and their conservation should be taken into account when planning any citrus IPM strategy.

Probability of Infection with Trypanosoma cruzi of the Vector Triatoma infestans Fed on Infected Humans and Dogs in Northwest Argentina

The probability that an uninfected Triatoma infestans would become infected with Trypanosoma cruzi after a single feed on people or dogs seropositive for T. cruzi was estimated in Amama, a rural village in northwest Argentina where transmission had resurged four years earlier. The prevalence of seropositivity for T. cruzi was 34.2% among 225 people tested, and 65.1% among 83 dogs tested. Parasitemia was detected by xenodiagnosis in 29.3% of 41 seropositive persons and in 85.3% of 34 seropositive dogs. Parasitemia decreased with age more sharply in seropositive people than in seropositive dogs. Seropositive humans infected 2.6% (95% confidence interval = 1.6%-3.6%) of 963 third or fourth instar nymphs fed once on them, whereas dogs infected 48.7% (44.7%-52.7%) of 610 nymphs. The probability of bug infection increased significantly with instar and was positively related to molting success. The infectivity to bugs of seropositive dogs was 12 times higher than that of seropositive children, and 100 times higher than that of seropositive adults. The weighted probability of infection of an uninfected bug fed randomly on any dog (0.3082) was about 50 times higher than that of bugs fed on any human (0.0062). Such differences in relative infectivity, combined with the relative host-feeding preference of domiciliary Triatoma infestans for dogs, reinforces the important role of domestic dogs as a risk factor for the domestic transmission of T. cruzi.

Population dynamics of two species of intestinal helminth in oystercatchers (Haematopus ostralegus)

The cestode Micrasomacanthus rectacantha and the trematode Psilostomum brevicolle are the two most common intestinal helminths of oystercatchers, Haematopus ostralegus, on the Exe estuary, England. Each was present in 57 of 60 birds, in numbers ranging from 1 to 9833 and from 1 to 182, respectively. Cockles (Cerastoderma edule) were used as paratenic host by M. rectacantha and as second intermediate host by P. brevicolle. Over 90% of the transmission of M. rectacantha from intermediate hosts occurred in winter, between cockles and juvenile birds. Exposure to M. rectacantha was highest in cockles from muddy sites, where up to 80% of older cockles were infected with 1–14 larvae. Exposure to P. brevicolle was similarly high at one sandy site. Juveniles also made up > 90% of the birds present on the estuary in summer, when significantly more worms were gravid. Estimates based on the numbers of uterine eggs per individual P. brevicolle showed that 8 % of the total Exe population of oystercatchers (ca. 200) contributed 51% of the eggs to the estuary. The results implicate host age, host feeding preference, and host population structure as important factors determining variation in helminth abundance in birds.

Investigations of the host feeding preferences of Sitona weevils found commonly on white clover (Trifolium repens) in the UK

AbstractA series of laboratory and field studies were done to evaluate a range of leguminous plant species for their feeding potential by adult weevils of the genus Sitona Germar. (Coleoptera: Curculionidae). Three species of Sitona, S. lineatus L., S. flavescens Marsh. and S. hispidulus F. all of which are found commonly on white clover (Trifolium repens L.) in the UK were offered a range of 11 legume species, T. repens (white clover, cv. Olwen), T. pratense L. (red clover, cv. Marcom), T. fragiferum L. (strawberry clover, cv. Palestine), T. hybridum L. (hybrid clover, cv. Tetra), T. incarnatum L (crimson clover), T. dubium Sibth. (lesser yellow trefoil), Lotus corniculatus L. (birdsfoot‐trefoil, cv. Leo), L. uliginosus Schkuhr. (large birdsfoot‐trefoil), Melilotus alba Desr. (white melilot), Medicago sativa L. (lucerne, cv. Europe) and M. lupulina L. (black medick) in two laboratory experiments. The weevils were offered a choice of these legumes in one experiment whilst in the other they did not have a choice of food material. These legumes were also sown in the field and a number of measurements of damage, together with counts of Sitona spp., were made. In the laboratory S. lineatus and S. hispidulus favoured some of the legumes to a greater or lesser extent than white clover. S. flavescens was more restricted in its feeding than the other two weevil species. In the field study S. lineatus invaded the experimental area quickly and tended to favour Medicago spp. and Melilotus spp. Later in the year S. flavescens dominated the sitona fauna on the experiment, with the exception of aggregations of S. lineatus on M. sativa and M. alba. In a separate screen of 5 varieties of white clover (cvs Donna, Menna, Kersey, Olwen and Grasslands Huia), cv. Olwen appeared to be the most susceptible to sitona attack.

Host feeding preference of Phlebotomus guggisbergi, a vector of Leishmania tropica in Kenya

Recently the sandfly Phlebotomus guggisbergi was found to be a vector of Leishmania tropica causing cutaneous leishmaniasis in the Laikipia focus, Kenya, but extensive searches have shed no light on the identity of the rural reservoir host(s). In order to discover more about the biology of the vector, a host feeding preference study was conducted on wild sandflies in their natural cave environment over a 6-month period. Solid state Army miniature (SSAM) traps, without light bulb, were suspended over cages with potential hosts or an empty cage control. The animals tested included sheep, goat, dog, cat, hamster, rabbit, giant rat (Cricetomys gambianus), crested rat (Lophiomys imhausi) and rock hyrax (Procavia capensis), all of which (except hamsters) are normally found in the vicinity of the study site. Sandfly collections from traps baited with goat, sheep, cat, dog, rabbit, or wild rodent species were significantly higher than the control, whereas trap collections with hamster and rock hyrax were not significantly different from the control. Numbers of sandflies collected from the goat, sheep and cat were significantly greater than from the rabbit and rodents. The sex ratio also varied between collections: larger animals attracted a higher proportion of female P. guggisbergi than did the smaller animals (P > 0.05). Therefore greater emphasis should be placed on surveying larger animals to assess their status as reservoir hosts for L. tropica in Kenya.

Host Plant Preference of Liriomyza sativae (Diptera: Agromyzidae) Populations Infesting Green Onion in Hawaii

Liriomyza sativae Blanchard was the only agromyzid leafminer species reared from foliage of green onion, Allium cepa L. var.‘aggregatum’, collected at two commercial farms in the Waianae area of Oahu, HI. Mean weekly densities of live leafminers reached levels > 13 larvae per leaf with mean seasonal densities of total mines as high as 20.6. In laboratory-conducted host plant-preference (choice and no-choice) tests, adult female L. sativae colonized from the Waianae and Hawaii Kai areas of Oahu exhibited significantly greater host feeding and ovipositional preferences for foliage of ‘Henderson’ bush lima bean, Phaseoluslimensis var. limenanus L. H. Bailey, compared to ‘multiplier’ onion. In no-choice tests, Waianae L. sativae reared on onion and bush lima bean deposited significantly more eggs in onion compared with bean-reared Hawaii Kai L. sativae. However, when given a choice between onion and bean, preferences of bean-reared Waianae L. sativae were not significantly different from Hawaii Kai L. sativae. Onion-reared L. sativae preferred onion significantly more than bean-reared L. sativae when provided a choice of the two host plants. Green onion has not been reported previously as a common host of L. sativae. Based on differences in feeding and ovipositional preferences of Waianae L. sativae compared with Hawaii Kai L. sativae, it was concluded that Waianae populations of L. sativae had broadened their host range to include green onion. Factors conducive to host plant expansion of L. sativae populations in the Waianae area of Oahu are discussed.

Foraging Patterns ofCyphoma gibbosumon Octocorals: the Roles of Host Choice and Feeding Preference

The distributions of small, relatively slow moving grazers are often portrayed as expressions of feeding preference. However, more careful analysis of such distribution patterns in concert with measurements of feeding suggests that the distribution patterns of the gorgonian-eating snail Cyphoma gibbosum may not reflect the influence of feeding preference alone. C. gibbosum is common at many sites in the San Bias Islands, Panama, occurring at densities ranging from 2-30 snails/100 m2. The movements and feeding of 244 labelled snails were followed at three sites in the San Bias during the summers of 1984-1986. Relative to gorgonian colony abundance C. gibbosum were preferentially found on colonies of Pseudopterogorgia spp., Pseudoplexaura spp., and Plexaura homomalla. Snails exhibited the same preferences in their movements between colonies, and often remained longer on those same gorgonian species.The prolonged occupancy on colonies of some species was the dominant factor controlling the amount of tissue c...

Host range and feeding preference of golden apple snail

Host range and feeding preference of golden apple snail

THE BLACK CITRUS APHIDS, TOXOPTERA CITRICIDUS (KIRKALDY) AND T. AURANTII (BOYER DE FONSCOLOMBE) (HOMOPTERA: APHIDIDAE)

AbstractThe geographical and temporal distribution, host plant range, feeding preferences and economic importance of the black citrus aphids, Toxoptera citricidus and T. aurantii, are discussed, with emphasis on the status of the two species in Australia.

Observations on the host range and feeding preferences of Aedes albopictus (Skuse).

The feeding habits of A. albopictus were studied during 1968 and 1969 on the island of Koh Samui, Thailand. The results indicated that A. albopictus commonly feeds on a variety of hosts including man, buffalo, pig, dog, and chicken. Specimens were captured in coconut plantations, a fruit orchard, and a forested area. The results also suggest that the host species used rank in attractiveness to A. albopictus as follows: (1) human, (2) pig, (3) and (4) buffalo and dog, and (5) chicken.