bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of simulated and natural rainfall on cochineal insects (Homoptera: Dactylopiidae): colony distribution and survival on cactus cladodes
Authors: MORAN V. C. , HOFFMANN J. H. 
Published: March 2008

ABSTRACT. 1. The distribution of Dactylopius opuntiae (Cockerell) colonies on Opuntia ficus‐indica (L.) Miller cladodes collected during a prolonged drought, was recorded for the proximal and distal portions of the cladodes, for the exposed and sheltered surfaces, the edges, and in relation to the proximity of the colonies to areoles at the base of the thorns.2. Most of the colonies were found on the more sheltered parts of the cladodes and a disproportionately large number of the colonies on exposed surfaces had settled below the areoles.3. Individuals in colonies on the exposed surfaces were all protected by a relatively hard, compacted wax cover and were thus less vulnerable to simulated rainfall than those on sheltered surfaces. Thorns provided some protection from simulated rainfall for individuals in colonies on exposed surfaces, but not for individuals on sheltered surfaces.4. Natural rainfall greatly reduced the numbers of colonies, but did not significantly change the distribution of the colonies on the cactus cladodes.5. Rainfall does not explain the observed distribution of D. opuntiae colonies on the cladodes, but does explain the poor performance of cochineal insects as biological control agents of prickly pear cacti in high rainfall areas.
The evolutionary dynamics of batesian and muellerian mimicry: similarities and differences
Authors: TURNER JOHN R. G. 
Published: March 2008

ABSTRACT. 1. The continuous spectrum of palatability can be divided without difficulty into two halves: the distasteful forms in one half tend to become models and muellerian mimics, the palatable forms in the other half to become batesian mimics.2. Most of the traditionally recognized differences between batesian and muellerian mimicry are valid and useful: negative versus positive frequency‐dependence, detriment versus benefit to the model, convergent evolution versus advergent evolution. None the less in both kinds, mimicry usually evolves by means of a major mutation whose effects are later modified. ‘Supergenes’ tend to be discovered more in batesian mimics than in muellerian mimics. This results from a complex interaction between natural selection on the one hand, and the origin of clusters of genes of related function through tandem duplication on the other.3. Adaptation is not simply the creation of the best of all possible worlds: what natural selection can do is limited by what is possible for the gene.
Tenebrionid beetles in the shortgrass prairie: daily and seasonal patterns of activity and temperature
Authors: WHICKER APRIL D. , TRACY C. RICHARD 
Published: March 2008

ABSTRACT. 1. Patterns of daily and seasonal activity for seven species of tenebrionid beetles, genus Eleodes, were investigated in the shortgrass prairie of northeastern Colorado. The relationship between time of activity, body temperatures, and rates of water loss of the beetles was examined in the field and in laboratory experiments.2. Common species were active from April until the end of October; however, asynchronous peaks of abundance occurred.3. Beetles were diurnally active with peaks of daily activity occurring 2–4 h after sunrise and before sunset. Less than a 2 h shift in mean time of activity occurred between seasons.4. Within species, body temperatures measured in the field closely corresponded to temperatures selected in an experimental thermal gradient; hence, species seemed to prefer particular body temperatures and were most active during times when those temperatures could be achieved. Body temperatures measured in the field approximated ambient temperatures measured in the vicinity of the beetle.5. Significant differences among several species were found for times of daily activity and corresponding body temperatures.6. Ability to resist water loss by evaporation was not correlated with daily or seasonal activity patterns.
Changes in egg colour, egg weight and oviposition rate with the number of eggs laid by wild females of the small heath butterfly, Coenonympha pamphilus
Authors: WICKMAN PER‐OLOF , KARLSSON BENGT 
Published: March 2008

ABSTRACT. 1. The colour of eggs laid by individual Coenonympha pamphilus (L.) (Lep., Satyridae) females changed over their lifespan. The first laid eggs were green, but after having laid about 100 eggs, females laid only yellow eggs.2. By following females in the field, or by capturing wild females, and noting the colour of their eggs, it was established that younger females showed higher oviposition rates and laid heavier eggs than older females.3. Hence, wild C.pamphilus females are unable to sustain a constant egg production by extracting amino acids or any other nutrients from nectar. We hypothesize that this is a general phenomenon in nectar feeding butterflies.4. The egg colour did not seem to match the colour of the substrate on which the female chose to deposit the egg.
Host plant relations in the planthopper genus Ribautodelphax (Homoptera, Delphacidae)
Authors: Den BIEMAN C. F. M. 
Published: March 2008

ABSTRACT. 1. Host plant relations of closely related species and pseudogamous triploid forms of the planthopper genus Ribautodelphax were studied.2. From field data and experimental results it is concluded that eleven European Ribautodelphax species and undescribed taxa are monophagous or oligophagous on different grass species. Only two Ribautodelphax species are found on the same grass species in the field.3. Differential host plant relations indicate that four recently discovered taxa are probably true species.4. Ribautodelphax species show a more restricted host plant range in choice experiments compared with breeding tests.5. Choice experiments indicate no differences in host plant preference between males and females of two Ribautodelphax species.6. No differences are found in host plant relations between bisexual species and associated pseudogamous triploid forms.
Arthropod faunal similarity of Bornean rain forest trees
Authors: STORK N. E. 
Published: March 2008

ABSTRACT. 1. Arthropod samples, collected by insecticide fogging ten Bornean lowland rain forest trees, were sorted to species and used to study some of the determinants of faunal similarity of these trees.2. Similarity indices were calculated between pairs of trees for guilds of beetles, beetle families and for different orders and other families of insects.3. Multiple regression analyses of five independent variables of the trees (taxonomic similarity, distance apart, vertical canopy overlap, similarity in tree height, epiphytic load) were carried out against these similarity indices.4. In eight of the eighteen insect groups analysed, taxonomic similarity of the trees is the most important variable affecting their species composition, accounting for a maximum of 29.4% of the variation.5. For the Homoptera, Gryllidae, Anthicidae, Chrysomeloidea and scavengers, distance between the trees and the similarity of the trees’epiphyte load have a greater effect on their faunal similarities than taxonomic similarity of the trees.6. The maximum variation accounted for by variables with significant T ratios was 38.6% in the Anthicidae. In four groups, the Formicidae, Heteroptera, Galerucinae and Corylophidae, none of the variables was significant.7. These data may support the view that for many insect groups there is less host‐specificity in the tropics than in temperate regions.
Carrion fly community dynamics: patchiness, seasonality and coexistence
Authors: HANSKI ILKKA 
Published: March 2008

ABSTRACT. 1. An outdoor cage experiment was conducted to test the theory that localized interactions facilitate coexistence of species breeding in ephemeral habitats. The same amount of larval resource (50 g of liver) but divided into one, two, four, eight or sixteen pieces was placed into each of fifteen cages once a week from June to September for 4 years.2. The cage populations were initially mixtures of thirteen species but after 4 years only Lucilia illustris (Meig.), Sarcophaga scoparia Pand. and S.aratrix Pand. remained. Lucilia illustris, by far the most abundant species in the field, predominated in every cage.3. Sarcophaga went extinct in most cages, but they survived in five cages in which the larval resource was much divided, in agreement with the theoretical prediction.4. Lucilia silvarum (Meig.) emerged about a week later than L.illustris in early summer; this phenological difference gave rise to a competitive asymmetry between the two species. This difference appears to explain why L.silvarum went extinct in the cages in 3 years, and it may explain why L.silvarum has consistently been less abundant than L.illustris in the natural community.5. Other differences in phenology, voltinism and rate of development in the flies are described, and such differences are suggested to facilitate regional coexistence of many species in seasonal environments.
Behaviour of late‐instar gypsy moth larvae in high and low density populations
Authors: LANCE D. R. , ELKINTON J. S. , SCHWALBE C. P. 
Published: March 2008

ABSTRACT. 1. Using scaffolding and night‐vision equipment, we observed fifth and sixth instars of the gypsy moth, Lymantria dispar (L.), on Quercus velutina Lam. in the field.2. In low‐density populations, larvae fed at night and spent the day resting in sheltered sites away from the canopy. In high‐density populations, larvae remained in the canopy throughout the day and night, and the amount of feeding during daylight hours increased with population density.3. Larvae at all population densities used a similar sequence of behaviours and sampled a number of leaves when selecting feeding sites, but larvae in high‐density populations switched feeding sites more frequently and fed continuously for shorter periods.4. Larvae seldom interfered with each other's feeding in any of the populations.5. When fifth instars were collected from the field and held for 24 h in an electronic feeding monitor, they maintained feeding rhythms that were characteristic of their source populations. Larvae spent more time crawling and less time feeding when offered foliage from high‐density rather than low‐density populations.
The effects of gregarine parasites on longevity, weight loss, fecundity and developmental time in the field crickets Gryllus veletis and G.pennsylvanicus
Authors: ZUK MARLENE 
Published: March 2008

ABSTRACT. 1. Gregarines, debilitating gut parasites, significantly reduced longevity and increased weight loss in the field cricket Gryllus pennsylvanicus Burmeiser when adults were kept on suboptimal diets, but in G.pennsylvanicus and G.veletis (Alexander and Bigelow) fed ad libitum, weight change, longevity, and fecundity were not significantly different in infected and control individuals.2. Adults harbouring gregarines at eclosion took significantly longer to develop from the second and third instars than did uninfected adults.3. Longevity of nymphs kept in the laboratory without food was decreased in infected individuals compared with uninfected ones, but not significantly so.4. The evolutionary and ecological implications of nonlethal parasites are discussed.
Effects of maternal age and adult diet on egg weight in the butterfly Euphydryas editha
Authors: MOORE RICHARD A. , SINGER MICHAEL C. 
Published: March 2008

ABSTRACT. 1. Euphydryas editha (Boisduval) (Nymphalidae) butterflies exhibited no consistent pattern of change in egg weight over their lifetimes. This was the case for captive butterflies fed diets containing sugars and amino acids, for butterflies fed diets containing only sugar, and for those left completely at liberty in their natural habitats between ovipositions.2. Two aspects of these results conflict with the findings of a previous study on the same subspecies. First, the previous study found that egg weight decreased with increasing maternal age. Second, this decrease was mitigated by addition of amino acids to the adult diet.3. We accept the findings of these previous workers that egg weight decreased with maternal age under their laboratory conditions. The discrepancy between their data and ours is likely to stem from the more natural conditions under which our insects were kept. Our own data from captive insects are not distinguishable from our field data.4. These results suggest that declines of egg weight with maternal age found in studies of other insects may also result from the artificial nature of laboratory conditions. We question whether such declines are general.5. We suggest that the second discrepancy between the two sets of work (effects of amino acids) stems from a design problem in the previous study.
Improved insect performance from host‐plant defoliation: winter moth on oak and apple
Authors: ROLAND JENS , MYERS JUDITH H. 
Published: March 2008

ABSTRACT. 1. We test the hypothesis that defoliation has short‐term and long‐term negative effects on performance of winter moth Operophtera brumata L. on two species of food plants: Garry oak (Quercus garryana Dougl.) and apple (Malus domesticus L.).2. Pupal weight (and hence potential fecundity of females) decreased with increased defoliation in the current year on both tree species.3. Pupal weight increased, however, with increased level of defoliation in the previous year.4. Increased weight of pupae from larvae which had fed on previously defoliated trees may buffer population decline by increasing fecundity of moths in the next generation.
Nesting behaviour of a subsocial African ball‐roller Kheper platynotus (Coleoptera, Scarabaeidae)
Authors: SATO H. , IMAMORI M. 
Published: March 2008

ABSTRACT. 1. The nesting behaviour of Kheper platynotus (Bates) was observed in the Tsavo West National Park, east Kenya.2. The construction of the brood ball seemed to be initiated by the female; thereafter, the male joined in. After its construction, the ball was rolled and buried by the male, whilst the female rode on the ball and occasionally helped the male.3. After burying the ball, the male came out on the ground, leaving the female under‐ground. The female coated the ball with soil and her excrement, and let it ferment for about 2 weeks. Thereafter, the female converted the ball into one to four free‐standing brood pears, and laid one egg in each pear. The number of pears produced depended on the size of ball. Even after oviposition, the female remained in the nest to care for the brood.4. Oocytes matured a little before being laid. Excess oocytes were gradually assimilated during brood care.5. Females seemed most likely to breed in two or more successive rainy seasons.6. Although male‐male aggression was observed, size assortative mating was not observed.
Lek behaviour of Drosophila cnecopleura in Hawaii
Authors: SHELLY TODD E. 
Published: March 2008

ABSTRACT.

Male spacing, aggression, and female visitation are described for a lek of Drosophila cnecopleura Hardy within a Hawaiian rainforest. The lek was located at a single tree of Pisonia umbellifera, and the males present defended individual leaves as mating territories. Observations were made in October 1986 and April 1987.
Approximately twice as many males were present at the lek in October than in April. At both times, males generally perched on the lowest leaves in the lek. Individuals did not remain on particular leaves for long periods of time but frequently moved among different territories.
Males engaged in two types of aggressive encounters, face‐offs and chases, and in all encounters the resident displaced the intruder.
Females were sighted at the lek 0.69 times/h in October and 0.23 times/h in April. Most of the leaves visited by females were among the lowest in the lek.
The contribution of multiple mating and spermatophore consumption to the lifetime reproductive success of female field crickets (Gryllus bimaculatus)
Authors: SIMMONS L. W. 
Published: March 2008

ABSTRACT.

The adaptive significance of multiple mating by female Gryllus bimaculatus (De Geer) was investigated.
Multiple mating prevented the depletion of sperm stores and, therefore, maintained high hatching success. This may not, however, explain the high frequency of remating in this species.
Male‐derived egg stimulants known to be passed with sperm at mating increased the number of eggs produced only when females mated throughout their lifespans.
Spermatophore consumption appeared to provide nutrients which, while they did not increase the quantity of eggs, increased egg quality as indicated by weight. Females who consumed spermatophores had a greater hatching success.
While females may derive non‐genetic benefits from mating, these are apparently long‐term benefits; females must mate throughout their lives in order to accrue them.
Since the benefits of mating may not be derived from individual males, the spermatophores and their contents in this species are best considered as mating effort.
Patterns of oviposition by Sandia xami (Lepidoptera, Lycaenidae) in relation to food plant apparency
Authors: JORGE SOBERÓN M. , CARLOS CORDERO M. , BETTY BENREY B. , PAULINA PARLANGE P. , GARCIA‐SÁEZ CARLOS , BERGES GERARDO 
Published: March 2008

ABSTRACT.

The butterfly Sandia xami (Reakirt) has a very clumped yearly pattern of oviposition on its food plant Echeveria gibbiflora D.C., and the mean number of eggs per plant is always very low.
Three features of host plants are highly associated with the probability of being oviposited upon: height of plant; degree of conspicuousness; and degree of isolation from conspecific plants.
The relative importance of these factors as predictors of the probability of oviposition change according to the time scale considered: height and conspicuousness are more important over short (weekly) time intervals whilst isolation takes precedence over longer (yearly) periods.
It is hypothesized that the clumped pattern of oviposition is responsible for the low numbers of the butterflies relative to their very abundant food plant.
Predation by wasps on lepidopteran larvae in an Ozark forest canopy
Authors: STEWARD V. B. , SMITH K. G. , STEPHEN F. M. 
Published: March 2008

ABSTRACT.

Predation by birds, crawling arthropods (ants, harvestmen, spiders), and social wasps (Vespula) spp. on introduced stocks of Heliothis virescens (Fabricius) larvae was investigated in a oak‐hickory forest canopy in northwestern Arkansas (U.S.A.).
Wasps, Vespula maculifrons (Buysson) and V.squamosa (Drury), removed over 90% of the larvae. Repeated visits to a feeding site by the same marked wasps accounted for removal of either a single larva or all larvae. Larvae pinned (punctured) to artificial leaves were selected over 70% of the time by wasps when compared to attachments that did not puncture larvae; however, unpunctured larvae were taken.
Crawling arthropods accounted for low levels of predation, and birds did not appear to prey on larvae. Apparently wasps removed larvae rapidly and efficiently, thereby depleting the feeding sites before other predators discovered the larvae.
Although attaching larvae to artifical hickory leaves provided an easy method for placing larvae into the forest canopy, a lower percentage of larvae were removed from these leaves compared to natural hickory leaves. Moving feeding sites did not influence the number of larvae taken.
Low temperature mortality of the peach‐potato aphid Myzus persicae
Authors: BALE J. S. , HARRINGTON R. , CLOUGH M. S. 
Published: March 2008

ABSTRACT.

The mean supercooling points of first instar and adult Myzus persicae (Sulzer) maintained at 20°C and cooled at 1°C min−1 were −26.6 and −25.0°C respectively.
The LT50 (temperature) of the same age groups drawn from the same population and cooled at the same rate were −8.1 and −6.9°C, indicating extensive pre‐freeze mortality in M.persicae under laboratory conditions.
Acclimation at 10 and 5°C did not affect supercooling but depressed the LT50 of both first instars and adult aphids.
Freezing of leaves during feeding did not increase mortality above that expected from the direct effects of low temperature.
The level of cold in different winters can be expressed in terms of the total number of frost days, and the frequency of abnormally cold days. Winter temperatures differ markedly in a vertical profile from the soil to the soil or grass surface, and then to the air (and foliage) above.
The time of the first record of M.persicae in suction trap samples is correlated with January and February temperatures except in the west of England and Wales. Further north December and January temperatures are relatively more important.
Winter temperatures and the resultant aphid mortality is a primary determinant of the timing of the spring migration.
The relationship of provision weight to adult weight and sex ratio in the solitary bee, Ceratina calcarata
Authors: JOHNSON MICHAEL D. 
Published: March 2008

ABSTRACT.

The female of the solitary bee Ceratina calcarata (Robertson) (Hymenoptera: Anthophoridae) excavates a tunnel in a pithy twig and then constructs and provisions a linear series of brood cells that make up her nest.
Adult females are, on the average, 1.3 times heavier than the males, a significant difference (P<0.001). There is no difference between the sexes in the amount of weight gained per unit of larval food.
Larger females occur because their provision masses are, on the average, 1.3 times heavier than male‐producing provision masses, a significant difference (P<0.001).
Because mothers invest more time and energy in their daughters, Fisher's theory predicts that they should produce more sons. When available resources are fewer in a given year as reflected in lighter provision masses, more males are produced during the year.
The observed sex ratio did not differ significantly from the expected, calculated as mean female weight/mean male weight and was male‐biased.
Unlike species which nest in pre‐formed tunnels, the sex of any brood cell except the innermost is random with respect to that cell's position in the nest and the tunnel's depth and diameter. The innermost position contained offspring with a female biased sex ratio (P<0.005).
Host and parasitoid recruitment for quantifying losses from parasitism, with reference to Pieris rapae and Cotesia glomerata
Authors: VAN DRIESCHE R. G. , BELLOWS T. S. 
Published: March 2008

ABSTRACT.

A technique for quantifying mortality due to insect parasitoids in insect populations is presented. The method is based on the measurement of recruitment to both the host susceptible stage and the pool of parasitized hosts.
The technique provides estimates of generational mortality due to parasitism and, when combined with estimates of population density, provides estimates of other mortality rates acting on both host and parasitoid populations. Such estimates are available both for the generation as a whole and for separate sampling periods.
The method is illustrated by application to two generations of Pieris rapae L. (Lepidoptera: Pieridae) and its larval parasitoid Cotesia (Apanteles) glomerata (L.) (Hymenoptera: Braconidae).