Large Field Cages Research Articles

Contribution of Natural Food Sources to Adult Longevity and Fecundity of Rhagoletis pomonella (Diptera: Tephritidae)

In a preceding systematic study in an apple orchard and its surroundings, we identified several natural substances upon which apple maggot flies, Rhagoletis pomonella (Walsh), were observed to feed. The primary objective of this investigation was to assess the identified natural substances for their contribution to apple maggot fly longevity and fecundity. Tests were carried out in small laboratory cages and in large field cages containing potted host trees. Results indicate that fly longevity can be sustained by carbohydrate obtained in the form of leachate on surfaces of host foliage. This explains the extensive “grazing” behavior of flies on nonvisible substances on host plant surfaces devoid of honeydew. Egg development, however, was not sustained by host foliage leachate. Bird droppings, aphid honeydew, and to a lesser extent hawthorn fruit leachate, contributed to moderate fly fecundity, whereas preparations of leaf surface bacteria, pollen, insect frass, and uric acid did not support significant egg development. Fecundity was greatest where flies were exposed to enzymatic yeast hydrolysate. Some practical implications of a better understanding of R. pomonella nutritional ecology are discussed, including the development of improved fruit fly attractants based on the identification of volatiles from natural nitrogenous sources such as bird droppings or insect honeydews.

An effective trapping method for field studies of opiine braconid parasitoids of tephritid fruit flies

A simple but effective trap for conducting field studies with opiine braconid parasitoids of fruit fly larvae was designed from yellow plastic balls containing an internal odor source and coated on the exterior with Tanglefoot. Tests of the trap in large field cages showed that it was simpler to use, less expensive, and more effective than previously reported designs.

Biological control of alligator weed: Unsuccessful attempts to control terrestrial growth using the flea beetleDisonycha argentinensis [Col.: Chrysomelidae

Biological control of alligator weed growing in aquatic habitats in Australia is successful but the agents, a flea beetleAgasicles hygrophila and a mothVogtia malloi, do not control terrestrial growth. Consequently another flea beetleDisonycha argentinensis was introduced into Australia specifically to control the terrestrial growth. Progeny of adults collected in Brazil from areas similar in climate and habitat to areas infested with alligator weed in Australia, were released but failed to become established. Eggs were laid by females released into a large field cage and some completed development, but the new adults failed to reproduce. Tentative conclusions are that microclimate or predation may have prevented establishment ofD. argentinensis but the results should not preclude attempts to establish this insect in North America, China or elsewhere.

Characteristics of dispersal in sexually mature dragonflies

Abstract. The population dynamics of a natural population of Sympetrum danae (Sulzer) were studied, by means of a mark—release—recapture method, to find indications of dispersal by mature adults. Additional information on orientation and the influence of phenotype (including age), density and weather was obtained by observations under natural conditions and in a large outdoor field cage. 80% of all mature adults caught around the natural pond were estimated to be immigrants. Considerable immigration was confirmed by the abdomen length of unmarked matures which did not accord with that expected from the locally emerged population. Total numbers captured and the minimum number known to be alive fell sharply at the time when most individuals were mature. At the same time, new matures continued to enter and disappear from the study area at an increasing rate. Dispersive behaviour (escape flights) in the field enclosure was primarily age dependent in both sexes: it occurred from an age of 25–30 days onwards. This coincides with the time‐lag between the emergence peak and increased dispersal in the field. Secondary effects on escape flights suggested that males tended to abandon low density areas. Males flew relatively more southward than females.

Evaluation ofMicrothrix inconspicuella, [Lepidoptera: Pyralidae], a potential biological control agent forEmex australis in Australia, carried out in apple orchards in South Africa

Host specificity tests carried out in the laboratory in Australia during 1977, showed thatMicrothrix inconspicuella Ragonot could develop on young apple leaves (Harleyet al., 1979). Field studies in unsprayed apple orchards in South Africa showed that some feeding occurred, but fewer than 40% of late instar larvae developed to adults when confined in sleeves on apple tree branches. No feeding or survival occurred in large field cages or in the open. Adults which developed from apple fed larvae were smaller, deformed, occasionally mated and laid fertile eggs but their progeny did not feed or develop on apple fruit or leaves. In conclusion,M. inconspicuella larvae did not develop on apple fruit or leaves in the field, damage was mainly limited to apples already injured and feeding on leaves was minimal. Under normal pest control practicesM. inconspicuella populations did not survive on any part of the apple tree or onE. australis growing under the trees.

Foraging behavior of a Dipteran leaf miner on exploited and unexploited hosts.

The foraging behavior of females of the leaf miner, Agromyza frontella (Rondani), (Diptera: Agromyzidae) when encountering unexploited or exploited alfalfa plants was studied in large field cages and in laboratory bioassays. Females did not recognize any exploited leaflets before contacting them and did not distinguish between leaflets with an egg or first instar larva and unexploited leaflets, even after contact. Only one fly oviposited in leaflets which contained 80-120 nutrition holes, one late second or third instar larva or which were marked with an epideictic pheromone in field cages. In laboratory bioassays females oviposited less in leaflets containing a second or third instar larva or an empty larval mine than in unexploited ones. Females foraging on unexploited leaflets engaged in area-restricted search and 10 of 11 females remained on the test plant for the full 60 min of observation. However, females foraging on exploited plants were much more active, spent a greater proportion of their time searching for suitable hosts, had the highest rates of visitation to all above ground plant parts and emigrated to the cage walls before 60 min had elapsed. These quantitative measures of foraging behavior indicated that females ranked plants after landing on them in the following order: unexploited plants >plants marked with pheromone or with many nutrition holes >plants with late instar larvae. The order of host ranking by foragers was in general agreement with the suitability of the host plants for larval survival, development and reproduction, as estimated from previous laboratory studies.Females of A. frontella foraging on unexploited alfalfa plants fed and oviposited significantly more often in the upper apical leaflets than in the lower, older leaflets. However, the choice of feeding site by flies on exploited plants did not vary with leaflet position (age), indicating that females fed in order to sample leaflet quality and that females investigated lower (older) leaves after they discovered that the preferred upper leaves were occupied. These data suggest that high quality oviposition sites may be limiting for A. frontella females, which could explain why superparasitism of leaflets sometimes occurs in nature, even when unexploited sites are available.

The Sterile Insect Release Method and the Importance of Thermal Conditioning Before Release - Field-Cage Experiments With Dacus-Tryoni in Spring Weather

We present a rationale for the strategy of suppressing the fertility and hence the rate of increase of target populations in spring by the release of sterile insects. Insects for mass release are normally reared in warm conditions and are potentially unsuitable for use in cold weather. A comparison was made of the effectiveness of warm- and cold-conditioned sterile flies in experiments in large field-cages during three successive spring seasons. Sterile males and females, and wild males and females were released into the cages in the ratio 2:2:1:1, respectively. Warm-conditioned sterile flies survived poorly between release and mating. Their mating competitiveness was inferior to that of the wild flies, and they were relatively ineffective in reducing their fertility. Sterile flies released in a cold-conditioned state (equal to that of the wild flies), survived as well as wild flies, and suppressed their fertility to an extent which indicates that their mating competitiveness can be equal to that of the wild flies, if the weather is not too severe. The concept of total competitiveness is introduced. If competitiveness is calculated by means of the ratio of sterile to wild flies that exists at release (rather than at mating), the resulting value is a measure of the potential of the sterile flies to survive to mating age, and to mate in competition with the wild flies. This value is especially pertinent to situations such as a puparial release, when there is a delay between release and mating. In such circumstances, it is needed for calculating the required ratio of sterile to wild insects to achieve the desired reduction of fertility (and thus rate of increase) in the target population.

Structural aspects of arboreality in titi monkeys (Callicebus moloch).

In nature titi monkeys spend virtually all of their time in trees. Preferences for certain heights above the ground or for trees per se are probably not, however, the immediate causes of this behavior, for animals housed in a large field cage containing many trees spend most of their time on a low-altitude artificial runway system. Further, the animals are not necessarily reluctant to touch the ground. To investigate the importance of perceived substrate structure as a determinant of arboreality, individuals were given opportunities to descend from their home runway and travel to food placed nearby on the ground. The animals travelled along a schematic model of a tree branch rather than across open ground when given a choice of these substrates, but they readily crossed the open ground when it was their only travel option. When the schematic model increased substantially in length and no longer provided a short route to food, it was still the preferred substrate. The results suggest that an abstract representation of a tree branch attracts and guides locomotion in titis, and that responsiveness to substrate characteristics contributes to arboreality in this species.

Mating Behavior of Platycotis vittata (Fabricius) (Homoptera: Membracidae)

Platycotis vittata females mate up to five times in large field cages. Females that mate more than once have more viable eggs and surviving offspring than those that mate once. Electrophoretic data indicate that sperm displacement occurs with sperm from the last male fertilizing most or all eggs. The last mating occurs when ovarian development is incomplete and several weeks before oviposition. We suggest that continued female receptivity appears to be a mechanism which promotes matings with males that have demonstrated their longevity. INTRODUCTION Parental care of offspring is common in the Membracidae (Wood, 1974, 1976a,b, 1977, 1978, 1979). When parental investment in offspring is high, females should choose mates which contribute to the fitness of offspring (Trivers, 1972; Thornhill, 1979). For females which brood only one clutch, the consequences of a mating with a genetically less fit male are greater than for those producing several broods resulting from multiple matings. In treehoppers, such as Platycotis vittata (Fabricius) and Umbonia crassicornis Amyot and Serville, longevity of females is critical to the survival of offspring. Nymphal survival is dependent on parent females making slits in the bark for feeding and females defending nymphs from predators (Wood, 1976a, b). Female U. crassicornis mate several days before eggs are deposited for about 1 hr (Wood, 1974). Umbonia crassicornis is a tropical and semitropical species living on evergreen legumes. Since there are no seasonal limitations on nutrient availability, it has continuous and overlapping generations throughout the year (Mead, 1962; Wood, 1974). Here we examine the mating behavior of Platycotis vittata, the only North American relative of Umbonia crassicornis. The life history, host plants and geographical distribution of P. vittata differ in fundamental ways from U. crassicornis, and this suggests mating behavior may also differ. Platycotis vittata occurs in the highlands of Mexico and North America, using a number of species of oak (Quercus). In both Florida and Ohio, this species has two generations a year. In the spring (in Ohio), eggs are deposited by overwintering females before buds break. Nymphs molt to adults in early June with mating beginning in late June and July. Mating takes from 8-24 hr. Oviposition, however, does not occur until late August or early September (Wood, 1976b). Thus P. vittata differs from U. crassicornis n its 2-month delay between the onset of mating and oviposition in addition to its extremely long mating times. We present data to show that this prolonged delay between the initiation of mating and oviposition affects the mating behavior of P. vittata. METHODS Behavior. -During each of 3 consecutive summers (1980-1982), aggregations of nymphs were collected in the New Jersey Pine Barrens and reaggregated on white oak (Quercus alba) in large field cages (1.8m x 1.8m x 1.8m) located in Newark, Delaware. When nymphs molted to adults, they were tagged with color-coded numbered tags. A total of 341 females and 312 males were tagged. When precopulatory pairing commenced, daily observations were made every hour throughout the day (1980-7 AM to 9 PM; 1981-82-8 AM to 8 PM) until all males had died (32-51 consecutive days). For I Department of Entomology and Applied Ecology, University of Delaware, Newark 19711. 2 Department of Zoology, Miami University, Oxford, Ohio 45056.

Contributions of Behavioral Primatology to Veterinary Science and Comparative Medicine

Behavioral primatology is a subdiscipline of the research area referred to as primatology. Like primatology, behavioral primatology is an eclectic field of study made up of researchers from diverse basic disciplines having very different historical roots and employing extremely different methodologies biased by emphases and assumptions dictated by their histories. Psychologists, zoologists, anthropologists, and psychiatrists make up the majority of those currently active in behavioral primatology, but others, including those in veterinary science, are active in research in the area. Behavioral data can be useful to veterinary scientists and to those in comparative medicine and are interesting in their own right. Veterinarians and medical scientists may specialize in behavioral disorders. In addition, those not directly interested in behavior itself may still make use of behavioral indices of potential physiologic and morphologic abnormality. Often an animal may be inadvertently stressed by social and nonsocial environmental factors, and such stress effects may be first and best recognized by behavioral means. A recognition by those not in the behavioral sciences of the basic feral behavior of primates can go a long way toward prevention or alleviation of both behavioral and physical stress of primates in captivity. Studies of free-ranging but captive troops are sources of information almost as good as, and sometimes even better than, field studies. In addition, there is a growing realization that "natural experiments" on primates in zoos can be of value, especially since many species held in zoologic parks are those least well known in more traditional captive research settings. It must be recognized that the findings from research done on captive primates living in large field cages are not directly comparable to those derived from more directly invasive but more experimental laboratory settings. A comparative perspective on captive environments, as well as on species, is strongly recommended. Behavioral primatologists, and particularly psychologists, have long been interested in behavioral development in various species of primates. A recognition of the importance of the effects of early experience, of species differences in development, of sex differences in development, of differences in species-specific social structures and in the relative plasticity of these, and of differences in symptoms of behavioral abnormality can contribute to the arsenal of techniques that might be used to improve the well-being of the primates and can help in the selection of appropriate animal models of disorder in humans for those in comparative medicine.(ABSTRACT TRUNCATED AT 400 WORDS)

Predation of Heliothis virescens (Lepidoptera: Noctuidae) Eggs by Geocoris punctipes (Hemiptera: Lygaeidae) Adults on Cotton 1

The impact of Geocoris punctipes (Say) predation of Heliothis virescens (F.) eggs was evaluated, using large field cages. Predator and prey densities tested were similar to average densities occurring naturally on cotton in Mississippi. The number of prey consumed per predator by intermediate predator densities (10,756 to 16,134/ha) increased significantly as prey density increased (16,134 to 48,402/ha), but the percentage of eggs consumed remained constant (1.0 to 2.0% per predator per 48 h). The similarity of these results to a type I functional response is discussed.

Plant, Host, and Parasite Interactions in the Host Selection Sequence of the Tachinid Lixophaga diatraeae 13

Tests conducted in a large field cage demonstrated that the tachinid, Lixophaga diatraeae (Townsend), were attracted to sections of the cage containing sugarcane infested with the larvae of the parasites host, the sugarcane borer, Diatraea saccharalis . Within sections of the cage, the parasites were able to distinguish between adjacent infested and uninfested plants. Further testing indicated that interactions between the host and its food plant are the source of attraction to larvipositing females. Larviposition by L. diatraeae on sugarcane stalks was significantly reduced at host feeding sites where larviposition and subsequent parasitization had occurred 24 h previously. This may prevent multiple parasitization of unsuitable hosts, thus conserving maggots.

PREDATOR REPRODUCTION AND THE OVERALL PREDATOR-PREY RELATIONSHIP

AbstractPrevious work described the effects of predation of pea aphids by adult coccinellids. That work has been extended to cover the entire reproductive cycle of the coccinellids. The relationship between amount of aphids eaten, and numbers of coccinellid eggs produced, was determined in the laboratory and used to predict numbers of eggs produced in the field. The survival rate of the eggs to adults, as a function of aphid density, was estimated in large field cages and in small enclosures. These relationships were incorporated into a population model for both predators and prey. The model has been validated against field data. It suggests that predator reproduction is optimized when conditions are very good. The significance for optimal foraging theory and biological control is discussed.

CONTROL OF APHID DENSITY BY A COMPLEX OF PREDATORS

AbstractA series of field experiments using large field cages were used to evaluate the role of aphidophagous predators on the population dynamics of the pea aphid, Acyrthosiphon pisum (Harris), on alfalfa, Medicago sativa L. The pea aphid numbers increased rapidly in the cages to as much as 5 times the density in the adjacent fields. The difference between densities in the cage and field decreased as the season progressed. No significant differences in fecundity of the aphids were found either in clip cages in the field and cages, or in the laboratory using field-collected aphids that were allowed to larviposit for 24 h. We used an earlier simulation model of the aphid to show that if fecundity alone were responsible it would have to be 3 times the maximum rate we have ever observed. The return of the aphid density to the field value when one cage was removed and the aggregation of predators show the importance of predator movements in limiting prey numbers.

A Functional Difference of the Individual Components of Spodoptera litura (F.) (Lepidoptera : Noctuidae) Sex Pheromone in the Attraction of Flying Male Moths

The functional difference of the two components of sex pheromon of Spodoptera litura, (Z)-9, (E)-11-tetradecadienyl acetate (compound A) and (Z)-9, (E)-12-tetradecadienyl acetate (compound B), in the attraction of flying male moths was analysed in a large field cage. Various dispensors containing compounds A, or B, or a mixture of both were used as lure sources and put in a continuous air stream generated by a fan. The flight courses of released male moths around these lure dispensors were recorded by a video recorder through a TV camera equipped with a night scope. Analysis of flight course traces indicated that the mixing state of compounds A and B in the air is an essential factor in inducing the upwind flight and searching flight of male moths around it. It was also ascertained that the concentration of compound A is an important signal for male moths to locate the pheromone source.

Paternity exclusion in six captive groups of Rhesus monkeys (Macaca mulatta).

Five genetic markers were employed to attempt to identify the fathers of 135 Macaca mulatta offspring living in large outdoor field cages. Family studies of two of these markers to confirm mode of inheritance of phenotypes had not heretofore been reported. Of the 284 exclusions required to identify the fathers of all 135 monkeys, 198 (or 70 percent) were possible using only these five genetic polymorphisms. For 58 (or 43 percent) of these 135 offspring the father was identified. These data were applied to estimate the association between dominance rank of fathers and reproductive success. Fertility of first- and second-ranking fathers was judged to be about twice as high as that of third- and fourth-ranking fathers.

Field Cage Evaluation of Predators for Control of Lygus hesperus Knight on Cotton

Predator efficiency of Lygus hesperus Knight was evaluated in a series of 5 treatments: (1) Geocoris pallens (Stal), (2) Nabis americoferus Carayon, (3) Chrysopa carnea Stephens, (4) the naturally occurring predator complex, and (5) Control or check. Geocoris pallens was very effective on egg-nymph or nymph populations of lygus bugs. Nabis americoferus was effective as a predator on the egg-nymph stages when confined to sleeve cages, but ineffective in large (183 cm × 183 cm × 366 em) field cages. Chrysopa carnea was ineffective. The natural predator complex provided 53–76% control of lygus bugs in the egg-nymph state.

Suppression of Heliothis spp. with Cottons Containing Combinations of Resistant Characters123

The use of nectariless, glabrous, and high-gossypol cottons and cottons with combinations of the 3 characters were evaluated against Heliothis species in replicated large field cages and in field plots. In cage tests, insect populations increased only 1.1 times (a maintenance population) between the 1st and 2nd generations on a cotton combining all 3 characters. Populations on glabrous plus high-gossypol cottons or on glabrous plus nectariless cottons increased 2-fold between the 1st and generations. Normal commercial types of cotton with none of the 3 characters had a 10–12-fold increase between generations. In the 1974 field tests, the glabrous plus high gossypol line yielded 700 lb/acre more seed cotton than the commercial check; and a high gossypol cotton (not glabrous) yielded 950 lb/acre more seed cotton. In field tests, glabrous plus high-gossypol cottons reduced populations of the bollworm, Heliothis zea (Boddie), and tobacco budworm, H. virescens (F.). A glabrous line suppressed larval populations by 68%, and 4 lines with a combination of both characters suppressed populations 60–88%. The nectariless character did not reduce insect populations because of the small size of the plots.

MATING BEHAVIOR IN RHAGOLETIS POMONELLA (DIPTERA: TEPHRITIDAE): V. VIRGIN FEMALE ATTRACTION TO MALE ODOR

AbstractEvidence from studies in large field cages indicated that odor from virgin male apple maggot flies, Rhagoletis pomonella (Walsh), was attractive to virgin females. Whether the principal role of this odor in mating behavior is in fact that of a female attractant or rather that of an aphrodisiac is uncertain and awaits further study.

Evaluation of Field Introductions of Two Insect Parasites (Hymenoptera: Braconidae) for Controlling Potato-infesting Aphids

Two hymenopteran parasites, Diaretiella rapae (M'Intosh) and an as yet undescribed species of Praon that were reared in an insectary on green peach aphids, Myzus persicae (Sulzer), infesting Chinese cabbage, were mass released as late-stage pupae (in mummified aphids) among growing, aphid-infested potato plants. From the number of parasitized aphids (from which parasites had not yet emerged) found subsequently on potato plants sampled weekly after the introductions, neither species of parasite exerted a measurable influence on aphid populations in large field cages, in small field plots, or in small fields. Both species of wasps have been reared from naturally parasitized potato-infesting aphids in northeastern Maine, both in the field and in the insectary, over a period of many years. In this experiment, the insectary-reared parasites apparently emerged satisfactorily as adults from introduced, parasitized aphids, but they did not search out and oviposit in aphids on nearby potato plants. In planning future experiments of this nature, it seems evident that much more information will be needed on the behavior of the adult parasites and their reaction to various meteorological factors in the field.