Competition for nectar resources does not affect bee foraging tactic constancy

1. Competition alters animal foraging, including promoting the use of alternative resources. It may also impact how animals feed when they are able to handle the same food with more than one tactic. Competition likely impacts both consumers and their resources through its effects on food handling, but this topic has received little attention. 2. Bees often use two tactics for extracting nectar from flowers: they can visit at the flower opening, or rob nectar from holes at the base of flowers. Exploitative competition for nectar is thought to promote nectar robbing. If so, higher competition among floral visitors should reduce constancy to a single foraging tactic as foragers will seek food using all possible tactics. To test this prediction, field observations and two experiments involving bumble bees visiting three montane Colorado plant species (Mertensia ciliata, Linaria vulgaris, Corydalis caseana) were used under various levels of inter- and intra-specific competition for nectar. 3. In general, individual bumble bees remained constant to a single foraging tactic, independent of competition levels. However, bees that visited M. ciliata in field observations decreased their constancy and increased nectar robbing rates as visitation rates by co-visitors increased. 4. While tactic constancy was high overall regardless of competition intensity, this study highlights some intriguing instances in which competition and tactic constancy may be linked. Further studies investigating the cognitive underpinnings of tactic constancy should provide insight on the ways in which animals use alternative foraging tactics to exploit resources.     

Crime or affliction? Rape in an African community

Amongst the Gush of southwestern Kenya instances of rape are frequently reported; this was true also in the colonial period and yet it seems that those cases which come to the notice of the authorities are few compared with the numbers which actually occur. While certain features of the traditional culture seem to have encouraged violent sexual assault, because in a patrilocal society miscreants are likely to victimize their relatives, that is women who are sexually taboo, the crime is considered a sacrilegious matter to be dealt with in the family, not by the secular authorities. Given the sacrilegious nature of the act the Gush are convinced that such behavior is involuntary and that the criminal is not a criminal but an afflicted person, motivated by the malevolence of the ancestral spirits or of jealous neighbors and kin. The author uses case material to illustrate various aspects of the Gush belief system in regard to criminal behavior in general and rape in particular.     

The impact of ticks on pheasant territoriality

Pheasants are competent reservoir hosts for the Lyme disease spirochaete, Borrelia burgdorferi s.l., and carry large, but highly over-dispersed, infestations of the vector ticks, Ixodes ricinus . The effects of experimental reduction of tick infestation levels on the survival and territorial behaviour of male pheasants were studied. Over three years in two woodlands in southern England, birds were marked individually and half were fitted with a slow-release acaricide, which substantially reduced their tick burdens from March to August. Acaricide treatment affected reproductive success but had no discernible impact on the survival rates of male pheasants. The degree of wattle inflation by males, an indicator of territorial status and a correlate of harem acquisition, was significantly greater among treated males. In each year, a significantly higher proportion of treated (overall 44%) than control (22%) males acquired harems. Males that acquired females ranged over small areas on field edges. By contrast, those with no females ranged more widely in woods and the adjoining fields, increasing their exposure to questing ticks. The relative contribution of such roving males to tick-borne pathogen transmission may thus increase.     

Dream Imagery and Emotion.

The relationship between prominent visual imagery and emotion within dreams was investigated in relation to E. Hartmann's (1996) contextualizing image (CI) theory and M. Seligman and A. Yellen's (1987) dual imagery theory. Fifty-nine students recorded dreams over a 2-week period and submitted 115 dreams for analysis. Participants recorded ratings of emotion type and emotion intensity in each scene. Prominent visual images were identified and scored for intensity and detail by independent judges. As hypothesized from Hartmann's theory, there was a significant positive relationship between CI intensity and emotion intensity in the CI scene, emotion intensity generally peaked in the CI scene, and dreams containing a CI had higher overall ratings of emotion intensity than non-CI dreams. The result for the correlation of detail of prominent imagery with emotion was inconclusive, with a low positive correlation across CI scenes. This raises the possibility that the CI is not a unitary construct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constancy of synaptic ribbon numbers in the retina of the arctic chary,Salvelinus alpinus

Synopsis At high latitudes, such as in Iceland, the daily photoperiod varies from almost continuous darkness in winter to virtually constant light in summer. Previous studies of detailed retinal structure in vertebrates have shown significant daily and annual effects of photoperiod. We sampled arctic charr in Iceland during the summer, including fish that were both light- and dark-adapted, during both day and night. We observed retinomotor responses characteristic of light- and dark-adaptation, but found no difference in the number of synaptic ribbons in the retina. The morpho-physiological changes, appearing as retinomotor responses, are thus not expressed at the synaptic level.     

The effects of two novel objects on the behavior of singly caged adult rhesus macaques.

Six female and six male adult rhesus macaques were given sticks and nylon balls as an attempt at simple cage enrichment. A latin square design was used to compare behavior during separate 4-week periods with each object and during a control period with no object. Frequency and duration of 15 different behaviors were recorded. Resting was the most common activity which decreased slightly in duration when the stick or nylon ball was present (P less than 0.02). The mean duration of stick use was longer than that of the nylon ball (P less than 0.01). No other behaviors changed significantly, including the frequency of abnormal behaviors such as self-abuse, stereotypic acts, and bizarre postures. Generally, these objects were used infrequently and led to few changes in the behavior of singly-caged adult rhesus macaques. However, they did appear to stimulate activity for some individuals.