Variety Of Arthropods Research Articles

Life history, demography, diet and habitat associations in the southwestern earless lizard, Cophosaurus texanus scitulus from northern and southern limits of its geographical range

AbstractI studied life history traits, demography, diet composition and habitat associations in the southwestern earless lizard, Cophosaurus texanus scitulus. Individuals from various age classes were sampled from populations at the northern (FCM) and southern (CAS) boundaries of its geographic range (FCM, foothills of Chinati Mts., Texas, USA; CAS, Castonos, Coahuila, Mexico). Males had higher growth rates as compared to females between the juvenile-to-yearling stages at both sites. Significant differences were also found for yearlings, and between yearling-to-adult stages. Growth rates decreased as a function of increasing age and were lowest in adults, and highest during the juvenile-to-yearling and yearling age classes. Earliest date on which a female was found to contain oviductal eggs was 19 May and 10 June, for the CAS and FCM sites, respectively. No females with oviductal eggs were found between 01 March and mid-May. Most females in reproductive condition had a SVL of 53-61 mm, and 57-64 mm, at the CAS and FCM sites, respectively, indicating that most females attain maturity at an age of 10-11 months. Clutch sizes were significantly smaller for females from the FCM site. Sex ratio was significantly biased toward females Survivorship was highest between yearling and adult age classes. Most lizards were found in areas with creosote and mesquite. These lizards are generalist predators that feed on a wide variety of arthropods.

GENDER SPECIFIC DIFFERENCES IN ACTIVITY AND HOME RANGE REFLECT MORPHOLOGICAL DIMORPHISM IN WOLF SPIDERS (ARANEAE, LYCOSIDAE)

Abstract Sexual dimorphism of locomotory organs appears to be common in a variety of arthropods, however, the underlying evolutionary mechanisms remain poorly understood and may be the consequence of natural or sexual selection, or a combination of both. I analyzed the activity pattern of seven cohorts of a wolf spider, Venatrix lapidosa, over four consecutive years. Males appear to be the more active sex in search for a mate as they show temporarily higher activity prior to the periods of female brood care. Morphometric data on leg length showed comparatively longer legs for males than females. Allometric leg elongation in all four legs of males arises only after the final molt suggesting its significance in reproductive behavior such as mate search. A comparative analysis of two Australasian wolf spider genera with different activity profile of females, Venatrix (sedentary females) and Artoria (vagrant females) provides further evidence that limb elongation in males mainly arises due to indirect male ma...

Pollination Processes in Idiospermum australiense (Calycanthaceae), an arborescent basal angiosperm of Australia?s Tropical Rain Forests

Idiospermum australiense (Diels) S.T. Blake, a rainforest canopy tree restricted to a few small populations in northeast Australia, is the only southern hemisphere representative of the Calycanthaceae. Pollination processes in Idiospermum were investigated. Flowers are protogynous, with some populations of the species being andromonoecious, whilst others are hermaphrodite. Over their 10 – 16 day floral lifespan, movements of floral organs enforced spatial and temporal separation of male and female floral function. Changes in colour and intensity of fragrance may also influence their attractiveness to potential pollinators. Pollen is present in large quantities, and appears to act as a reward for floral visitors. Insect trapping was carried out both within flowers, and immediately adjacent to inflorescences. A wide variety of arthropods was trapped, with thrips being the most abundant. Other arthropods were trapped, including fourteen species of beetle. For arthropods other than thrips, the mean numbers of adults trapped on flowers remained more or less constant throughout the floral lifetime. However, there was a significant interaction between floral age and the number of pre-adult arthropods present – as the flower aged, the mean number of larvae and eggs per flower increased. The flowers appear to act as sheltered mating and brooding sites for small insects.

Amphibians occurring in soybean and implications for biological control in Argentina

Abstract The diversity and diet composition of amphibians were examined in soybean of the Cordoba and Entre Rios Provinces of Argentina, investigating their potential as biological control agents of herbivores species. A total of 15 anuran species belonging to three families were detected in the two crops. The numbers of individuals found in soybean and the variety of arthropods they consumed suggest that anuran populations could be important biological control factors of soybean arthropods.

Time budget, foraging activities, diet and occurrence of aspergillosis in captive yellowheads (Mohoua ochrocephala)

Instantaneous and focal animal sampling were used to describe various activities and foraging methods of eight captive yellowheads. They spent, on average, 74% of their time foraging, and most often foraged on the ground. Gleaning was the most frequently employed feeding method. The birds’ diet consisted of a proprietory insectivore meat mix, a variety of arthropods and miscellaneous foods. Nectar consumption was observed in this species for the first time. The study has implications for the prevention of avian aspergillosis in captive birds.

How to study subterranean army ants: a novel method for locating and monitoring field populations of the South East Asian army ant Dorylus (Dichthadia) laevigatus Smith, 1857 (Formicidae, Dorylinae) with observations on their ecology

A new method employing palm oil as bait was developed for studying the distribution and ecology of subterranean army ants. In SE Asia the hypogaeic army ant Dorylus laevigatus was found to be very common in both forested and open environments. More than 10000 workers were found at individual baits. The workers cooperatively dig a three-dimensional tunnel network into the soil. Over a period of 72 days no emigrations of D. laevigatus could be detected, a first indication of a facultatively stationary way of life in this ant. Encounters with Pheidologeton silenus about food resources were observed. In feeding experiments D. laevigatus readily took a variety of arthropods and annelids but ignored starch containing vegetables as food. The rare hypogaeic D. (Alaopone) cf. vishnui could be collected for the first time in India and Sri Lanka. Also the epigaeic D. (Anomma) nigricans from Africa were found to be attracted to palm oil. The oil-method thus provides the opportunity to detect and monitor populations of army ants of the genus Dorylus in tropical and subtropical habitats.

Functional conservation of the wingless—engrailed interaction as shown by a widely applicable baculovirus misexpression system

The expression patterns of the segment polarity genes wingless and engrailed are conserved during segmentation in a variety of arthropods, suggesting that the regulatory interactions between these two genes are also evolutionarily conserved. Hypotheses derived from such comparisons of gene expression patterns are difficult to test experimentally as genetic manipulation is currently possible for only a few model organisms. We have developed a system, using recombinant baculoviruses, that can be applied to a wide variety of organisms to study the effects of ectopic expression of genes. As a first step, we studied the range and type of infection of several reporter viruses in the embryos of two arthropod and one vertebrate species. Using this system to express wingless, we were able to induce expression of engrailed in the anterior half of each parasegment in embryos of the fruit fly Drosophila melanogaster. Virus-mediated wingless expression also caused ectopic naked ventral cuticle formation in wild-type Drosophila larvae. In the flour beetle, Tribolium castaneum, ectopic wingless also induced engrailed expression. As in Drosophila, this expression was only detectable in the anterior half of the parasegment. The functional interaction between wingless and engrailed, and the establishment of cells competent to express engrailed, appears to be conserved between Drosophila and Tribolium. The data on the establishment of an engrailed-competent domain also support the idea that prepatterning by pair-rule genes is conserved between these two insects. The recombinant baculovirus technology reported here may help answer other long-standing comparative evolutionary questions.

Review Biology and ecology of trombidiid mites (Acari: Trombidioidea)

Most mites of the family Trombidiidae are ectoparasites in the larval stage and free-living predators in the deutonymphal and adult stages on a variety of arthropods, among which are pests of many economic crops. This paper provides an updated review of their systematics, life history, reproduction, behaviour, predator-prey and parasite-host relationships, and population dynamics, with particular reference to their possible role in biological control. © Rapid Science Ltd. 1998

Predation of Two Common House Spiders upon Medically Significant Pests

Two common house spiders prey upon medically significant pests. The remains of 15 brown recluse spiders were discovered in the webs of Steatoda triangulosa. Achaearanea tepidariorum was observed preying upon the lone star tick. Although spiders are generally considered unwelcome inhabitants of homes, two species of common house spiders in Kansas prey upon medically important pests. This note records the predation of Achaearanea tepidariorum (C. L. Koch) (Araneae: Theridiidae) upon the lone star tick, Amblyomma americanum (Linnaeus) (Acarina: Ixodidae), and the predation of Steatoda triangulosa (Walckenaer) (Araneae: Theridiidae) upon the venomous brown recluse spider, Loxosceles reclusa Gertsch and Mulaik (Araneae: Loxoscelidae). Rocky Mountain spotted fever and tularemia are transmitted to the human population by the three active stages of the lone star tick (Waddington, 1975). Bites of the brown recluse spider cause local dermonecrosis (Dillaha et al., 1964) and systemic reactions leading to death (Lessenden and Zimmer, 1960; Taylor and Denny, 1966). A. tepidariorum is a common cosmopolitan species found in and around buildings throughout Kansas (Scheffer, 1904). Its diet consists of a wide variety of arthropods and even an occasional vertebrate (McCook, 1889). Fitch (1963) identified the discarded remains of spider wasps (Sceliphron and Trypoxylon), flies, beetles, leafhoppers, roaches and harvestmen (Leiobunum) beneath webs of this species. A. tepidariorum also preys upon spiders, including the purseweb spider, Sphodros fitchi Gertsch and Platnick (Araneae: Atypidae) (Guarisco, 1988). On 25 July 1990, a female house spider in a web located between the floor and baseboard of the Kansas Biological Survey map room, rapidly approached a lone star tick crawling across the floor beneath the web. The spider immediately enswathed her prey, carried it to the center of the web and began to feed upon it. The tick and spider were captured for subsequent identification.

Intraplant Distribution of Three Nabis Species (Hemiptera: Nabidae), and Impact of N. roseipennis on Green Cloverworm Populations in Soybean

The within-plant distributions of Nabis americoferus (Carayon), N. roseipennis Reuter, and N. rufusculus Reuter differ in soybean. N. americoferus adults are located in the upper canopy, whereas adults of the other two species are located lower in the plant canopy. Early-instar nymphs of all three species are vertically separated from their respective adult stages. Nabids were observed to feed on a wide variety of arthropods including pest, beneficial, and innocuous species. The seasonal abundance of nymphal N. roseipennis and the within-plant overlap of its distribution with early instars of the green cloverworm suggested that it may be an effective predator on this pest species. N. roseipennis nymphs were successful in reducing numbers of green cloverworm larvae in the field in the presence of other predators and alternative prey under minimally modified conditions. Starting densities of 20–25 third instars per 0.9-m plot resulted in up to 50% reduction in subsequent green cloverworm populations.

A Flight-Cage Actograph for Recording Circadian Periodicity of Pink Bollworm1 Moths2

The activity recording system used to monitor circadian periodicity in pink bollworm moths, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), is presented. The actograph provides a permanent record while eliminating the use of light and direct observation for studying nocturnal periodicity. A graphic recorder, preamplifier, and power supply register the output of a vibration-sensitive transducer mounted on an isolated metal cage. Vibrations produced by movements of moths in the cage indicate the overall levels of activity which are associated with specific behavioral events. Response to light, foraging behavior, mating, and relative inactivity are indicated by characteristic patterns. Rhythms produced by 20 moths during a continuous 14-day trial include entrainment, free-run in dark, and subsequent reentrainment. Circadian periodicity was dependent on photoperiodic induction. This system is highly adaptable and may be used with a variety of arthropods.

Effects of Range Treatment With 2,4-D on Food Habits of Rodents

The food habits of rodents inhabiting shrub grass and perennial forb ranges in western Colorado were investigated to determine the kinds and proportions of foods eaten, the effects of range treatment with 2,4—D on food habits, and the degree of competition for food among rodents inhabiting these ranges. Treated and control areas at each site were trapped periodically and estimates were made of plant coverage. A part of the stomach contents of each rodent was mounted on a slide and was examined with microscopes. The volume in percent of each food item was estimated and recorded. Deer mice exhibited a seasonal variation in diet. Their winter food was primarily seeds whereas arthropods made up a large part of the diet during the summer months. Cutworms comprised almost one—half of the food ingested during June. Male and female deer mice showed no difference in diet, but the diet of deer mice varied with age group. fugi were found in the stomachs of rodents, particularly during the fall months. Deer mice occasionally ingested parts of small mammals. Grass seeds comprised a larger proportion and forb and shrub seeds a smaller proportion of the diet of deer mice inhabiting areas treated with 2,4—D than that for untreated areas. The availability of these food items appeared to be responsible for these observed differences in diet. Least chipmunks ate a variety of arthropods, seeds, and leaves, and, like the deer mouse, exhibited seasonal variation in diet. Although there was no significant difference in diets on treated and control areas, the influence of the availability of certain seeds was evident. Range treatment with 2,4—D had no effect on the diet of montane voles. Leaves and stems of forbs and shrubs comprised a large part of the summer diet on both treated and control areas on Grand Mesa. Differences in diet with sex and age were observed. The greater abundance of montane voles on treated areas appears to be due to an increase in grass cover and not to an increase in available food. No competition for food was observed among deer mice, least chipmunks, and montane voles at the population levels sampled in this study.

The experimental host range of the arthropod-borne animal viruses in arthropods

Thirteen selected arthropod-borne animal viruses were introduced parenterally into 1 arachnid, and 8 insects representing 6 orders. Serial passages were attempted with these 117 combinations and were successful, indicating propagation, in 58 of them. In some cases the viruses survived in individual arthropods for many months through molting and metamorphosis without apparent injury to the host. An affinity of the viruses for the central nervous system of the arthropod was observed. It is evident that these viruses possess a high potential for propagating in a variety of arthropods. However, this potential is not exhibited by all members in the same degree. It gradually diminishes as one passes from group A through group B, and becomes very restricted in certain of the group B viruses and in certain viruses not of these two groups. A theory is proposed that this is an evolutionary gradient starting with an ancestral type of wide host range and ending with those closely adapted and restricted to certain hosts.

Components of the catch curve of Culex annulus in Singapore.

REGULAR cycles of flight and/or feeding activity are known to occur in a variety of insects, particularly mosquitoes, and theories have been advanced to account for the form and regularity of the observed rhythms; references to most recent work on mosquito-biting cycles have been given by Haddow1. In discussing the biting cycle of Anopheles leucosphyrus in Borneo2, I have myself suggested that the catch curve is the resultant of two separate factors: a cycle of arrival at the bait, and a cycle of activation to produce feeding activity; also that arrival at the bait is conditioned by initial spatial distribution, a cycle of activation to flight activity, and factors orientating such flight. With regard bo the latter, it was suggested that the mosquitoes arrive at the bait by a process of random wandering, or at least one not orientated by the bait itself. Recently, my attention has been directed to a paper by Webster and DeCoursey3, demonstrating that the daily catches in a variety of arthropods are in fact determined by a process of random arrival at the trap, in accordance with a theoretically derived equation of the form: where K is the initial population, C the cumulative catch, t time, and a and b are constants.