CHEMICAL COMMUNICATION IN INSECT COMMUNITIES: A GUIDE TO INSECT PHEROMONES WITH SPECIAL EMPHASIS ON SOCIAL INSECTS

• 1 Chemical communication plays an important part in the lives of insects, and particularly in lives of those that live in groups or social organizations.
• 2 Chemicals which are used in communication in the general sense are called semiochemicals, and there are a number of subdivisions recognized under this title.
• 3 Pheromones are a category of semiochemicals which are used for communication between individuals of the same species.
• 4 Pheromones are in turn subdivided into primer and releaser pheromones. The former produce a relatively long-lasting physiological change in the receiver, and the latter stimulate the receiver to some immediate behavioural response.
• 5 Far more is known about releaser pheromones at present because they are easier to study.
• 6 Nine categories of releaser pheromone are recognized here, used by both social and non-social insects.
• 7 Sex pheromones are widely used to bring the sexes together for mating, and they have been extensively studied in Lepidoptera.
• 8 Invitation pheromones, encouraging the species to feed or oviposit at an explored site, are not extensively known.
• 9 Aggregation pheromones are designed to bring individuals together into groups which may be temporary in sub-social insects, or permanent in social insects.
• 10 Dispersal or spacing pheromones are used by other species to reduce intraspecific competition for scarce resources.
• 11 Alarm pheromones are a broad and sometimes unclearly defined group which communicate alarm or attack, chiefly in colonial species.
• 12 Trail pheromones, applied to a surface by an individual, to be followed by another, are confined to Hymenoptera, Isoptera and a few Lepidoptera as far as is known.
• 13 Territorial and home range pheromones may be widely distributed, but as yet few of them have been recognized.
• 14 Surface and funeral pheromones are even less well known. Surface pheromones may play a large part in species or colony recognition.
• 15 We can expect the number and complexity of pheromones to be much greater in social insects, a part of the subject which until now has received relatively less attention.
• 16 As our understanding of the subject grows we may expect other categories to be added to this list.

     

ORGAN TRANSPLANTATION: CONTEMPORARY SUNNI MUSLIM LEGAL AND ETHICAL PERSPECTIVES

The problems that organ transplantation poses to the Muslim mind may be summarized as follows: firstly, a muslim believes that whatever he owns or possesses has been given to him as an amānah (trust) from Alla¯h. Would it not be a breach of trust to give consent for the removal of parts of one's body, while still alive, for transplantation to benefit one's child, sibling or parent? Secondly, the Sharā'ah (Islamic Law) emphasizes the sacredness of the human body. Would it not then be an act of aggression against the human body, tantamount to its mutilation, if organs were to be removed after death for the purpose of transplantation? In this paper I attempt to illustrate how the Muslim jurists have tried to resolve the dilemma of Muslims by providing them with certain guidlines based on the original sources of Islam, namely, the Qur'n and the Prophetic tradition. In order to assist the followers of other religious traditions to grasp the gravity of the problem posed by organ transplantation to the Muslim mind, I begin by discussing the opinions of Muslim jurists on the issue of utilization of human parts. Thereafter, I touch upon the resolutions taken by the various Islamic Juridical Academies on the issue in question. Finally, I shed light upon the inclusion of organ donation in a Muslim Will and the enforceable nature of such a will     

A multivariate analysis of cropping effects on Irish ground beetle assemblages (Coleoptera: Carabidae) in mixed arable and grass farmland

The assemblage of carabid species trapped over a 3 yr period in eight separate but contiguous fields was analysed by Canonical Correspondence Analysis (CCA), Seven of the fields were subject to arable crop rotations involving a mixture of autumn and early spring‐sown cereals (wheat or barley), late spring‐sown crops (potatoes, sugar and fodder beet and maize) and short‐term uncultivated grass leys, The eighth field was an established ‘permanent’ grass pasture of at least 50 yrs standing, Pooled samples collected in the first half of the growing season (April‐June) showed clear evidence of soil cultivation effects on community structure, Systematic exclusion of samples and re‐analysis distinguished the fauna of firstly, old pasture samples, samples from ley pastures of increasing age and finally samples from fields with different times of soil cultivation, In the latter analysis, the main effects of soil cultivation were related to differences in ground cover over the winter and a direct effect of spring soil cultivation on autumn breeding populations, The ordination of pooled catches for the second half of the growing season (July‐September) could not be related to known year, field or crop cultivation variables, The underlying species ordination suggested that later in the summer the effect of crop cover on soil microclimate may mask cultivation effects by influencing the post‐emergence dispersal of autumn‐breeding populations and the reproductive success of spring‐breeders, The combination of earlier soil cultivation effects, and probably microclimatic influences later in the season, resulted in the strong distinction of whole season carabid catches from individual fields, It is concluded that the uniqueness of individual field histories may provide a mechanism to promote the co‐existence of ecologically similar species within the farmed landscape and enhance the abundance and bio‐diversity of species in the face of routine soil cultivation.     

Change of Dufour gland contents with age of workers of Formica sanguinea (Hymenoptera: Formicidae)

ABSTRACT The Dufour glands of newly emerged adult workers of F.sanguinea Latr. are almost empty, but the gland fills slowly over several months. The amount and composition of the secretion varies between individuals but the mean values change with age, the composition reaching its final value only in old foraging workers. Undecane is the major component for most of the period, but its proportion decreases with age. The amount of (Z,E)-α-farnesene increases with age and finally becomes the major component. The change in composition may reflect changes in worker function.     

Identification of a component of the trail pheromone of the ant Pheidole pallidula (Hymenoptera: Formicidae)

ABSTRACT The poison gland of minor workers of P.pallidula. Nyl. contains 3-ethyl-2,5-dimethylpyrazine which induces trail-following in other workers, but does not account for the full trail-following effect of one worker's poison gland. No pyrazines were detected in major workers and their glands do not contain the pheromone.