Two-way Choice Research Articles

A test of the dear enemy phenomenon in the Eurasian beaver

We tested the hypothesis that Eurasian beavers, Castor fiber, display the dear enemy phenomenon; that is, they respond less aggressively to intrusions by their territorial neighbours than to intrusions by nonterritorial floaters (strangers). This ability could be advantageous in facilitating differential treatment of wandering strangers versus established neighbours. Territorial beavers were presented with scent from neighbouring and stranger adult males. Thirty-nine different active beaver families, 18 in 1998 and 21 in 1999, were presented with a two-way choice between two pairs of experimental scent mounds; mounds with castoreum from a neighbour and a stranger, and mounds with anal gland secretion from a neighbour and a stranger. Direct observations of the families during evenings showed that: (1) beavers sniffed both castoreum and anal gland secretion from a stranger significantly longer than from a neighbour, and (2) beavers responded aggressively (stood on the mound on their hind feet, pawing and/or overmarking) significantly longer to castoreum, but not to anal gland secretion, from a stranger than from a neighbour. When experimental scent mounds were allowed to remain overnight and the beavers' responses were measured the following morning, the beavers' responses were significantly stronger to both castoreum and anal gland secretion from a stranger than from a neighbour. These findings indicate that Eurasian beavers can use scent to discriminate between neighbours and strangers, thereby supporting existence of the dear enemy phenomenon in this species. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

The Induction of Low Nocturnal Secretion of Melatonin Caused by Reverse Feeding Rhythms Depends on Availability of Macronutrient Diets

The present study investigated the effect of single chow diet and two-way dietary choice between a protein-rich and a carbohydrate-rich diet ingested during free access or daytime access (08.00-16.00 h) on the rhythms of ingestion and on nocturnal levels of serum melatonin and pineal N-acetyltransferase activity in rats. Animals with free access to the single or the choice diets displayed a circadian rhythmicity of total food intake with peaks at the beginning, the middle and the end of the dark phase. Rats fed the dietary choice displayed a preference for carbohydrate at the beginning, and a preference for protein at the middle and the end of the dark phase. Under daytime feeding access, both dietary conditions resulted in only one peak of total intake at the beginning of the access period. Rats fed the choice diets on the daytime feeding schedule initially preferred carbohydrate to protein but this preference disappeared subsequently. Nocturnal peaks of serum melatonin and pineal NAT activity were lower with daytime access to dietary choice compared to ad libitum access. The results suggest that in a two-way selection of macronutrients, feeding cycle can directly act on the rhythms expressed within the pineal gland.

FEMALE MATE PREFERENCE AND REPRODUCTIVE ISOLATION IN POPULATIONS OF THE STRIPED MOUSE RHABDOMYS PUMILIO

AbstractLaboratory experiments were conducted to study female mate preference in three allopatric populations of the striped mouse Rhabdomys pumilio, an African murid rodent. The three populations (Alice, Goegap, Irene) represent the extremes of the distribution range of the species in South Africa. Using two-way choice tests, virgin females were exposed to: (i) males of the same population (homotype) and those of another population (heterotype) in whole animal choice tests, or (ii) the odiferous bedding of homotype and heterotype males. Generally, females significantly preferred homotype stimulus males or their odour. This preference was only evident when females were in oestrus, suggesting that females were choosing potential mates. In addition, prior association with males is not needed for the establishment of female mate preference, since females were never exposed to adult males of any of the populations prior to testing. The only exception was receptive Goegap females which showed equal preference for homotype and Alice heterotype males. Mate preference in these two populations is asymmetric since Alice females showed strong preference for homotype males over Goegap males. The results indicate that divergence has occurred in allopatry, resulting in populationspecific communication signals and in particular olfactory cues, assortative mate choice, and pre-mating reproductive isolation.

The Host Range ofEccritotarsus catarinensis(Heteroptera: Miridae), a Potential Agent for the Biological Control of Waterhyacinth (Eichhornia crassipes)

Abstract The host range of Eccritotarsus catarinensis was determined using 33 plant species to assess the risk of using this insect, a native of South America, for the classical biological control of waterhyacinth ( Eichhornia crassipes ) in Australia and Papua New Guinea. The results, in conjunction with the results of Hill et al. (1999) who tested 67 species (mostly South African), strongly suggest that E. catarinensis is restricted to the Pontederiaceae, a family of aquatic plants. All five species of Pontederiaceae in the Australian testing, E. crassipes, Pontederia cordata, Monochoria vaginalis, M. cyanea, and M. australasica, were suitable for insect development. Colonies persisted for at least four generations on E. crassipes, P. cordata, and M. vaginalis. Two-way choice and multiple-choice preference trials were conducted and discussed. E. catarinensis did not exhibit a clear preference for waterhyacinth over other Pontederiaceae in these trials. Most oviposition occurred into the upper surface of the lamina during laboratory testing despite observations that the underside was preferred in the field. Although not considered suitable for release in Australia, this insect may be useful in other countries where more serious waterhyacinth problems occur and where M. vaginalis is a serious weed, such as in Southeast Asia.

Effect of Diet Textural Characteristics on the Temporal Rhythms of Feeding in Rats

To examine whether the diurnal rhythms of protein-rich and carbohydrate-rich diet ingestion can be altered by presenting the diets in different textural forms, adult male Wistar rats were assigned to two dietary groups. One group received a two-way choice between high-protein powder and high-carbohydrate granular (HPP-HCG) diets. In the other group the textures were reversed [high-protein granular and high-carbohydrate powder (HPG-HCP) diets]. Rats fed HPP-HCG diets selected significantly less protein (kcal) vs. rats fed HPG-HCP diets, during the 24-h and 12-h dark phase and during the 4-h early and late dark phases. Carbohydrate intakes of the two dietary groups were not significantly different. Total caloric intake for the HPG-HCP dietary group was significantly higher than that of the HPP-HCG dietary group during the 24-h and 12-h dark phase. Body weight was significantly lower in rats fed HPP-HCG diets. In conclusion, macronutrient-rich diets presented in different textural forms alter protein-rich diet ingestion and total energy intake.

Oviposition Preferences of the Polyphagous Moth Choristoneura parallela (Lepidoptera: Tortricidae): Effects of Plant Species, Leaf Size, and Experimental Design

The fireworm Choristoneura parallela (Robinson) is a major pest of cranberry in New Jersey. Eggs typically are laid on the leaves of various weed species, and larvae disperse onto cranberry by ballooning. We used laboratory-reared moths and greenhouse experiments to investigate oviposition preferences among 3 weed species: greenbrier, Smilax rotundifolia L.; leatherleaf, Chamaedaphne calyculata (L.); and sheep laurel, Kalmia angustifolia L. In no-choice tests conducted in screen cages using cuttings, leatherleaf received the most egg masses whereas the other species did not differ. In this test there were no differences among species in the latency to the 1st egg mass; and the latency between the 1st and 2nd egg masses did not differ for greenbrier compared with the other species but was shorter for leatherleaf than for sheep laurel. The results were similar in 3-way choice tests conducted in screen cages using cuttings with leatherleaf receiving the highest percentage of egg masses and the other species not differing. However, a different preference hierarchy was found in 3-way choice tests conducted in plastic boxes using a single leaf of each species: greenbrier received the highest percentage of egg masses, leatherleaf received more than sheep laurel, and sheep laurel received no egg masses. Two-way choice tests using paired leaves in plastic boxes showed that larger greenbrier and leatherleaf leaves were preferred over smaller ones of the same species, but that leatherleaf was preferred over sheep laurel even when sheep laurel leaves were larger. These results demonstrate that this moth exhibits oviposition preferences among plant species but that the preference hierarchy depends on the experimental situation, and that both the species and the size of individual leaves can be factors.

Sibling recognition in the beaver: a field test for phenotype matching

The hypothesis of kin recognition by phenotype matching predicts that relatives can be identified without previous contact, and/or that cues used for recognition can be learned indirectly from a third but related individual. This hypothesis was tested in the field using 22 beaver,Castor canadensisfamilies. Individually identifiable beavers were provided with a two-way choice between two experimental scent mounds, one of which was scented with the anal gland secretion (AGS) from an unfamiliar sibling of the test subjects, the other with AGS from an unfamiliar non-relative. Beavers showed less strong territorial responses to AGS from their siblings than to that from non-relatives. The mates of the test subjects, which were not related to, or familiar with, either of the AGS donors, also responded less strongly to the AGS from their mates' siblings than to that from other unfamiliar non-relatives. This discrimination was not shown when castoreum samples were tested instead of AGS. Therefore, it was concluded that (1) information about kinship in the beaver is coded in the AGS but not in the castoreum, (2) the mechanism of phenotype matching is used in beaver sibling recognition, and (3) the cue used in phenotype matching can be learned and used for recognition of related individuals by an unrelated individual.

Negative assortative mating in the white-throated sparrow, Zonotrichia albicollis: the role of mate choice and intra-sexual competition

Abstract. White-throated sparrows are dimorphic, mating disassortatively by morph. In laboratory choice trials, females of both morphs preferred tan-striped males when allowed to interact with males (two-way choice), but displayed no preferences when one-way mirrors did not allow stimulus males to interact with them (one-way choice). Males of both morphs displayed significant preferences for white-striped females in one-way choice trials, but not in two-way trials. During within-sex competition trials, white-striped birds were dominant to tan-striped birds of the same sex. These results suggest that negative assortative mating is maintained in part because white-striped females outcompete tan-striped females for access to the preferred tan-striped males. Tan-striped females then pair with the less preferred white-striped males. A three-step process is proposed to account for the high level of negative assortative mating seen in the white-throated sparrow.

Individual Discrimination by Olfactory Cues in Mice (<em>Mus musculus</em>): A multiple Choice Confirmation

The ability to discriminate four individual conspecifics by olfactory cues in laboratory mice was investigated. Adult male mice of the CD-I outbred strain were water deprived and placed in a Plexiglas four-arm maze, twice a day, five days a week. Subjects were assigned to two groups: Training and Control. Training mice were trained by water reinforcement (a drop of water) to choose the maze's arm containing the sawdust of one of four donors (adult males, same strain), while for Control mice the association between sawdust and reinforcement was continuously varied. Data collected during three weeks showed that Training mice made significantly fewer errors in finding the water than Control mice, thus confirming the results of previous experiments based on a two-way choice that proved mice to be able to discriminate conspecifics individually by olfactory cues.

An evaluation of the role of internal cues in the pathogenesis of parkinsonian hypokinesia

Our animal studies suggest that the basal ganglia provide an internal non-specific cue to trigger movement and imply that Parkinson's disease involves a deficiency in this cueing mechanism. Indeed parkinsonian patients typically rely upon external visual cues. To assess the effects of such non-specific cueing mechanisms on movement, we examined patients' utilization of a variety of auditory cues. Ten patients suffering from Parkinson's disease, and their matched controls, pressed buttons at a series of two-way choice points sequentially down a pathway, both when the latter remained illuminated throughout its length, and when it had to be followed from memory alone. In other experimental conditions, auditory cues were also provided, either contingent upon the previous response, at its initiation (a medium level of advance information) or at its completion (a low level of advance information), or as a series of regularly paced (non-contingent) auditory cues (from a metronome). In addition to error data, we recorded down time (DT, time to initiate each next response) and movement time (MT, time to execute each next response). However, both DT and MT measurements showed that parkinsonian patients were enormously disadvantaged by the absence of external cues. While contingent auditory cues were of some help, the performance of patients with Parkinson's disease was dramatically improved by the provision of non-contingent auditory information. Moreover, parkinsonian patients, unlike controls, were greatly affected by the length of individual sub-movements, especially in the absence of external cues. When the pathway to be followed remained illuminated, sub-movement length had little effect. We conclude that for well-learnt, predictable sequences the basal ganglia provide a non-specific internal cue that is necessary for switching between one movement and the next in a movement sequence, and also for development of preparatory activity for each sub-movement in the sequence.

Diet selection in pigs: choices made by growing pigs given foods of different protein concentrations

ABSTRACTTo test the proposition that growing pigs, when given a choice between two foods, are able to select a diet that meets their requirements, and to investigate the rules of diet selection, four foods (L, A, B and H) with similar energy yields, but different concentrations of crude protein (CP) (125, 174, 213 and 267 g CP per kg fresh food respectively) were formulated. The four foods were offeredad libitumeither singly, or as a two-way choice using all the six possible pairs, to 40 individually caged pigs from 12 to 30 kg live weight. On the single foods the rate of food intake fell from 1001 to 971 to 961 to 868 (s.e.d. 40) g/day (F < 0·05) as the protein concentration of the foods increased from L to H; the growth rate followed an opposite trend (492, 627, 743 and 693 (s.e.d. 31) g/day respectively;P< 0·01). When the pigs had to select between two foods limiting in protein (L and A) the less limiting one was preferred (710 (s.e. 200) g A per kg total food intake; the protein concentration of the selected diet was 160 (s.e. 10) g CP per kg). On the choice between B and H (a choice between a food with protein concentration close to requirements and a food with protein excess) the lower food was markedly preferred (928 (s.e. 4) g B per kg total food intake; the protein concentration of the selected diet was 218 (s.e. 1) g CP per kg). When the animals were given a choice between two foods, a combination of which was non-limiting (pairs LB, LH, AB and AH), the protein concentrations of the selected diets were not different between treatments (208, 204, 202 and 205 (s.e.d. 13) g CP per kg respectively) and they also declined systematically with time and weight. The growth rate of the animals on these pairs were 752, 768, 769 and 763 (s.e.d. 54) g/day (P > 0·05), which were not significantly different from the highest growth rate achieved on a single food. The results suggest that pigs, when given a choice between a suitable pair of foods, are able to choose a balanced diet and to change its composition to reflect their changing requirements. The choice-feeding method may well be useful as an effective and economic way of estimating and meeting requirements, and of measuring the growth potential of pigs.

The importance of male and female acoustic behaviour for reproductive isolation in Ribautodelphax planthoppers (Homoptera: Delphacidae)

The importance for reproductive isolation of species-specific acoustic differences between closely related Ribautodelphax planthopper species is tested by measuring responses to playbacks of both conspecific and heterospecific signals. Females respond to heterospecific male calls at about 80% of the conspecific response level, irrespective of the degree of cross-insemination of the combination involved. In a combination involving R. albostriatus, a taxonomically more distantly related species, female response levels are only 15–33% of the normal level. Study of the development of both female responsiveness and receptiveness shows that response levels correspond fairly well with insemination levels. Female heterospecific response is far too high to explain isolation between the species. Female answers to heterospecific males calls have normal response-delay times and durations. When offered a two-way choice between female playback calls, males significantly more often approach the conspecific call in almost all combinations tested. Offering only a heterospecific female signal induces males to call, but not to search. Males are capable of maintaining at least part of the sexual isolation by distinguishing between different female calls. This seems in conflict with the popular theory that the sex with the greater parental investment, here the female, should be exerting the choice.

Mechanisms of action of some vegetable oils against Sitophilus zeamais motsch (Coleoptera: Curculionidae) on wheat

The insecticidal activity of some fixed vegetable oils against Sitophilus zeamais on wheat was investigated. Test oils from different sources and levels of purity effectively reduced the development of progeny by similar amounts. When all wheat grains were treated with oil, X-ray studies showed that oviposition by S. zeamais was not affected, although there was considerable subsequent mortality. However, in a two-way choice experiment S. zeamais showed an oviposition preference for grains not treated with oils. Freshly applied oils caused some mortality in adult S. zeamais only at rates above 10.5 ml/kg, but this effect disappeared when treated grains were aged for 14 days before bioassay. Application of oils at up to 17.5 ml/kg to grains pre-infested with late stage larvae/pupae confirmed that these oils had no appreciable effect against such stages. X-ray studies established that the main toxic action of the oils was against the eggs and early stage larvae.

Maintenance of innate feeding preferences by a polyphagous insect despite ingestion of applied deleterious chemicals

AbstractThe question of whether the appearance of a novel deleterious chemical in a preferred host plant could alter the relative degree of preference by a polyphagous insect during its lifetime was considered. The behavioral preference of fall armyworm, Spodoptera frugiperda (J. E. Smith), for corn (Zea mays L.) over red kidney bean Phaseolus spp. was quantified in a two‐way choice test, and followed by a no‐choice test in which the same larvae were fed either treated or untreated corn. Each treatment consisted of one of 15 compounds, including 13 naturally occurring allelochemicals and two synthetic insecticides. None of the test chemicals had any inherently deterrent effect at the rates tested. Deleterious effects on the larvae during exposure included reduced growth, reduced size, irritancy, and in some cases death. After this exposure the two way choice test was repeated. All test compounds failed to elicit a change in relative preference during the final two‐way choice test. However, larvae exposed to gossypol and chrysanthemum monocarboxylic acid ester fed less than expected during the latter stages of no‐choice conditions. The degree of aversion learning by each larva was related to the degree of prior sickness it had experienced.RésuméPersistance des préférences alimentaires innées d'un insecte polyphage malgré l'absorption de substances chimiques nocivesNous avons examiné si l'introduction d'une substance chimique nocive dans la plante‐hôte préférée pouvait modifier la hiérarchie des choix durant le reste de la vie d'un insecte phytophage. Le comportement de préférence de Spodoptera frugiperda pour le maïs (Zea mays) vis à vis des Phaseolus, a été quantifié dans un dispositif à choix binaire, ont suivi des expériences au cours desquelles les chenilles devaient s'alimenter, soit sur maïs sain, soit sur maïs traité. Chaque essai concernait un composé chimique (15 au total), 13 étant des substances allélochimiques naturelles, 2 des insecticides de synthèse. Aux concentrations étudiées, aucun des produits n'a eu d'effet dissuasif. Les effets nocifs pendant l'exposition sur les chenilles comprenaient une croissance et une taille réduites, une irritation et, dans quelques cas, la mort. Aucune des expériences de choix binaire, avec des chenilles ayant subi cette exposition, n'a modifié les préférences. Cependant les chenilles, qui avaient été exposées au gossypol ou à l'acide monocarboxylique éthyl ester de chrysanthemum, ont consommé moins pendant les stades ultérieurs que ce que l'on pouvait attendre en absence de choix. Le degré d'aversion acquis par chaque chenille dépendait de l'importance des maux qu'elle avait subis précédemment.

Influence of Host Plant on Deterrence by Azadirachtin of Feeding by Fall Armyworm Larvae (Lepidoptera: Noctuidae)

The tetranortriterpenoid azadirachtin, a derivative of neem, caused more inhibition of fall armyworm, Spodoptera frugiperda (J. E. Smith), larval feeding on cotton seedling foliage compared with lima bean seedling foliage. This difference may be related to the relative proportions and interactions of naturally occurring stimulants and deterrents in the plants, because two-way choice tests demonstrated that lima beans are the preferred host. Although azadirachtin does not strongly deter feeding by fall armyworm larvae on lima beans, properties of this chemical inhibit their growth and provide good crop protection within 7 d. Implications of these results for the use of feeding deterrents and other naturally occurring compounds as crop-protection agents are discussed.

Sibling recognition in the white-footed mouse, Peromyscus leucopus: Association or phenotype matching?

This study was an attempt to determine whether sibling recognition in P. leucopus is mediated by phenotype matching or by association. A measure of social preference in a two-way choice apparatus was used to infer sibling recognition. Experiment 1 demonstrated that, when given a choice in the preference apparatus, adult mice spent significantly more time on the side with a familiar sibling (a sibling that had been reared together with the test animal) than on the side with an unfamiliar non-sibling (a non-sibling that had been reared apart from the test animal). In experiment 2, pups were cross-fostered within the first 3 days of birth such that four combinations of sibship and association were formed: siblings reared together, siblings reared apart, non-siblings reared together, non-siblings reared apart. Mice showed a significant preference for siblings reared together versus siblings reared apart, and for non-siblings reared together as compared to siblings reared apart. There were no significant differences in time spent near siblings reared together versus non-siblings reared together, nor between siblings reared apart versus non-siblings reared apart. These results demonstrate that association during early life, and not genetic relatedness per se, is the most important factor mediating sibling recognition and preference in this species. It is suggested that the major difference between phenotype matching and recognition by association is that, in the former case, animals learn family-specific identification cues, while in the latter, they learn individually-distinctive cues that cannot be generalized to unfamiliar relatives.

THE EFFECT OF HORIZONTAL DIFFERENTIAL PRISM ON THE BINOCULAR CONTRAST SENSITIVITY FUNCTION

The photopic binocular contrast sensitivity function is measured using a two-way resolution choice sinusoidal-grating target with horizontal differential prism before the right eye of one subject (AHT). A significant drop in sensitivity occurred with 3 prism-dioptres base-out or 4 prism-dioptres base-in prism at an observation distance of 5.9 m, and with 2 prism-dioptres base-out or 8 prism-dioptres base-in at 50 cm. An equivalent effect was confirmed with three additional subjects at a test distance of 2 m. The relationship between these results, the passive position, and the fusional reserves is discussed and reference is made to the effect of vertical differential prism.

Individual variation in oviposition preference in the butterfly, Colias eurytheme.

We examined intra-population variation in oviposition preference in the pierid butterfly, Colias eurytheme. Females' preferences were tested in the laboratory, using two-way choice tests between the potential hosts, alfalfa and vetch. There were consistent differences in oviposition preference among females within a population. Larval and adult experience had little or no effect on females' preference. These results suggest that the intra-population variation in oviposition preference is genetically based, but the results of experiments designed to estimate the heritability of oviposition preference were not conclusive. We suggest that intra-population variation in host selection characters may play a key role in shifts to new host plants.

Alcohol intake in selected lines of mice: Importance of sex and genotype.

Mice selected by McClearn and Kakihana for differences in ethanol-induced sleep time were used as subjects. In Experiment 1, mice from the long-sleep (LS) and short-sleep (SS) lines were offered a choice of water or solution GS consisting of 3% glucose and .16% sodium saccharin (w/v); or a choice of water or solution GS + E that contained GS solution plus 4% ethanol (w/v). In Experiment 2, mice from the first experiment were provided with a three-way choice among water, solution GS, and solution GS + E. In both experiments, SS mice (alcohol-insensitive) consumed more GS + E than LS mice (alcohol-sensitive). In addition, female mice drank considerably more GS + E solution than male mice. Thus, consumption of sweetened ethanol in both a two-way choice (water and GS + E) and a three-way choice (water, GS, and GS + E) is dependent on both genotype and sex. High genetic sensitivity to ethanol was associated with low consumption, and vice versa. Although females consumed more alcohol than males, famales of these lines have not been previously found to show lower sensitivity to acute alcohol administration.

Altersabhängiges Lernen bei der Japanischen Wachtel (Coturnix coturnix japonica)1

The main question of our investigation is: Do there exist age-specific learning abilities in animals? 120 QUAILS (Coturnix coturnix japonica) of 12 different age groups (between one day and 20 weeks) were tested in a combination apparatus 0y using two training methods. 60 quails were trained with decreasing (1), 60 other quails with increasing learning assistance (2). In each case the learning period lasted 5 days after which the animals were tested in a two-way choice apparatus and in a simple maze. Retention was tested 3 weeks later. - The 2 methods led to different results. In general the younger animals learnt better than the other ones when trained by method 1. No differences in learning performance between the 12 age groups were obtained by method 2.