Innate Attraction Research Articles

Innate attraction supplants experience during host plant selection in an obligate plant-ant

In order to assess the relative contributions of innate attraction and environmentally-induced preference to nest plant selection by the obligate plant-ant Tetraponera aethiops, we submitted both mature and callow workers to paired choice tests using the leaves of four plant species, including their natural host plant Barteria fistulosa. Mature workers taken from nature as well as mature workers after 25 days of laboratory breeding (with or without contact with B. fifstulosa leaves) always showed a great preference for shelters made with the leaves of B. fistulosa. Similar results were obtained with callow workers isolated from any plant material during the first 25 days of imaginal (=adult) life or during pre-imaginal development. But those reared in contact with test-plant leaves for the same two periods showed significantly less preference for B. fistulosa than did the controls. As a result, experience gained during the larval and nymphal stages as well as during the first part of adult life (i.e. pre-imaginal as well as early learning) was demonstrated in T. aethiops, but in this situation of species-specific interaction it reinforces innate attraction as both larvae and adults live in contact with B. fistulosa in nature. These results are discussed in comparison with previous data collected on arboreal ants not specifically paired with a plant, for which an environmentally-induced preference can supplant innate attraction.

Tropical arboreal ant mosaics: innate attraction and imprinting determine nest site selection in dominant ants

The modalities of nest site selection have, until now, been a key factor missing in the understanding of the arboreal ant mosaic, the manipulation of which could be used to favour one ant species to the detriment of others in biological control. We compared two dominant African arboreal ants of economic importance, Tetramorium aculeatum (Myrmicinae) and Oecophylla longinoda (Formicinae). The two species differed in terms of innate attraction to nesting site plants, their hierarchies of attractiveness being nearly inverse. Winged females and workers were confronted with choice tests using four plant species. By using winged females and workers originating from one of the plants to be tested, we showed the existence of a familiarisation process which can supersede innate attraction in both species. We recorded the same effect in neonatal workers bred in the laboratory in contact with a tested plant for 25 days after emergence, while mature workers could not be conditioned. There is, therefore, early learning, with a sensitive period after which the influence of the environment ceases, suggesting that this is a true imprinting process. Choice tests using neonates produced from larvae and pupae bred in the laboratory in contact with the leaves of each tested plant permitted us to demonstrate the existence of pre-imaginal learning. Nest site selection therefore depends on innate selective attraction and on environmental factors whose effect begins at the larval stage. There is, therefore, the potential to “control” imprinting, allowing one ant species to be favoured to the detriment of others in monospecific tree crop plantations.

Effect of Adult Experience on the Host-Location Behavior of the Aphid ParasitoidAphidius colemaniViereck (Hymenoptera: Aphidiidae)

The effect of experience on the host location behavior ofAphidius colemaniViereck females was investigated by means of wind-tunnel bioassays and a glasshouse release experiment. In laboratory tests with bell pepper(Capsicum annuumL.), naive females showed little innate attraction either to uninfested plants or to plants heavily infested with the green peach aphid(Myzus persicaeSulzer). However, a brief preflight experience with this aphid/plant combination resulted in a significant increase in the proportion of females making complete upwind flights to such plants in the wind-tunnel. Subsequent experiments demonstrated that exposure to aphids alone, to uninfested plant material, or to infested plants of a different species (radish [Raphanus sativusL.]) was not sufficient to cause this increase in responsiveness: the effect was only seen in females that experienced the complete “target” aphid/host–plant combination. In the glasshouse experiment, females which were given a brief (15 min) exposure to aphid-infested plants before release subsequently found and parasitized significantly higher numbers ofM.persicaethan did naive females of the same age. The implications of these findings for applied biological control are discussed.

Extrafloral Nectar, Honeydew, and Sucrose Effects on Searching Behavior and Efficiency of Microplitis croceipes (Hymenoptera: Braconidae) in Cotton

The influence of extrafloral nectar, sucrose, or whitefly honeydew on host- and food-searching behavior of Microplitis croceipes (Cresson) females was investigated. Retention time, parasitization rate, time allocation to host damaged leaves and time interval between subsequent host attacks were compared in different cotton, Gossypium hirsutum L., patch treatments containing Heliocoverpa zea (Boddie) hosts. Parasitoids that were starved for 2 d before release to patches with either sucrose or extrafloral nectar showed longer retention times and higher rates of parasitization than those not able to feed. The presence of food in the patch increased the time allocated to damaged leaves, but did not reduce the time interval between host attacks. Parasitoids that fed in patches with honeydew showed a similar performance to parasitoids in patches without any food, probably as a result of the relatively low quantity and quality of this food source for M. croceipes . The initial and subsequent detect-ability of different food sources was also investigated. More parasitoids found extrafloral nectar than sucrose in a first release. However, in a subsequent release, nectar and sucrose were found equally fast. Therefore, parasitoids showed an innate attraction to extrafloral nectar, whereas learning may have influenced orientation to sucrose. The importance and use of cotton extrafloral nectar as food source for adult parasitoids and the means of using extrafloral nectar as part of a pest management strategy in biological control are discussed.

Evidence for Lack of Homing by Sea Lampreys

Recently metamorphosed sea lampreys Petromyzon marinus were captured in the Devil River, a tributary to Lake Huron, during summer and autumn 1990. They were tagged with a coded wire tag and returned to the river to continue their migration to Lake Huron to begin the parasitic (juvenile) phase of their life. During the spawning run in spring 1992 when the tagged animals were expected to mature and return to spawn, sea lampreys were trapped in nine tributaries to Lake Huron, including the Devil River; 47,946 animals were examined for coded wire tags, and 41 tagged animals were recovered. None of the 45 mature sea lampreys captured in the Devil River in 1992 were tagged, a proportion (0%) significantly lower than the proportion of the recently metamorphosed sea lampreys tagged in 1990. The distribution of tag recoveries among streams lakewide, however, was proportional to catch. Tagged sea lampreys did not appear to home, but instead seemed to select spawning streams through innate attraction to other sensory cues.

Recent neutron scattering investigations of liquid4He

Abstract Despite almost thirty years of investigation (I), neutron scattering studies of the excitations of liquid 4He are still providing surprise and excitement. Why there should be this continuing interest is not difficult to understand. First of all there is the innate attraction of this fascinating and unique substance. The hope that neutron scattering would help provide a microscopic understanding of the phenomenon of superfluidity had, until recently, been largely unfulfilled; in this article I shall indicate how recent neutron measurements are leading to a new understanding of the elementary excitations of liquid 4He and their connection to the superfluid state. But thereis alsocontinuing interest intheinteractions between excitations and here (isotropic)4He, with its single well-defined (phonon-roton) mode-which is significantly affected by modest pressure and temperature changes-may be considered as a “model” substance forthe study of the excitations of condensed matter.

Representations of astronomers in literature

The depiction of astronomers as characters in fiction during the last four centuries provides a useful historical indication of the changing popular perception of astronomy and its practitioners. It is apparent that lay attitudes to astronomy, even in any given period, are complex. On the one hand there is the continuing, innate attraction which the spectacle of the night sky has for people of all ages, the sense of wonder it generates and the perception of astronomy as a pure science, free from military and environmentally damaging spin-offs. But, on the other hand, astronomy poses particular and radical challenges to the humanist tradition and these have elicited from many writers not only expressions of anguish and confusion but, at times, a personal attack on the astronomers who were considered responsible for the unwelcome views.

Tourism in the centrally-planned economies of Europe

The current size and future potential of the international tourism market in the centrally-planned economies of Europe is examined. As destinations, they are under-performing in comparison with Western destinations on the measures of visitor arrivals and receipts (in absolute terms), as well as a proportion of national product and total exports. Major constraints include travel restrictions, poor quality of touristic provisions, inadequate marketing and promotion, and political difficulties. But, based on their innate attractiveness, opportunities exist to develop tourism in these countries through increasing openness and receptivity to joint foreign-capital ventures, and improved marketing. Of crucial importance is the upgrading of the total tourist product.

Preferential Behaviour of Sarotherodon (Oreochromis) Mossambicus (Pisces: Cichlidae) Fry To Maternal Models and Its Relevance To the Concept of Imprinting

The effect of previous exposure on the later preferential responsiveness of Sarotherodon mossambicus fry to maternal models was investigated. All fry were removed from their mother's mouth as eggs and hatched and reared under artificial conditions so that they were never exposed to natural maternal stimuli. In all experimental groups fry were exposed to a maternal model on day 10 post-hatching (the first day they are normally released from the mother's mouth) and tested 24 h later for their preferential responsiveness toward two models. In Experiment I separate groups of fry were exposed on day 10 to one of two maternal models of intermediate innate attractiveness. Control fry exhibited no preferential behaviour on day 11 while all groups of experimental fry responded preferentially to the same ('split') model, regardless of the model to which they had been previously exposed. In Experiment II fry exposed for 15 or 60 min on day 10 responded preferentially to a potentially supernormal 'black pit' model as opposed to the 'split' model, again regardless of the model to which they had been previously exposed. In Experiment III groups of fry were exposed to one of two 'preserved female fish' models which differed in the degree of contrast between their broody colouration and the background colouration of the fish; virtually no preferential behaviour was exhibited by these fry. The results showed that after fry have been exposed to maternal stimuli they will then respond preferentially to whichever model forms a closer match with their initial perceptual schema of the broody mother. All experimental groups of fry in Experiment I responded preferentially to the 'split' model, regardless of which model they had previously been exposed to; the same pattern emerged in Experiment II. The fry failed to respond preferentially in Experiment III possibly because they could not discriminate between the two models or because both models fit their initial perceptual schema equally well. It was concluded that while social bond formation in S. mossambicus fry is affected by early experience, there are stronger innate constraints on the process than would be expected from traditional studies of imprinting.