The Trail Pheromone of the Venomous Samsum Ant, Pachycondyla sennaarensis Author(s): Ashraf Mohamed Ali Mashaly, Ashraf Mohamed Ahmed, Mosa Abdullah Al—Abdullah, Mohamed Saleh Al—Khalifa Source: Journal of Insect Science, 11(31):1-12. 2011. Published By: Entomological Society of America DOI: http://dx.doi.org/10.1673/031.011.0131 URL: http://www.bioone.org/doi/full/10.1673/031.011.0131 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Journal of Insect Science: Vol. 11 | Article 31 Mashaly et al. The trail pheromone of the venomous samsum ant, Pachycondyla sennaarensis Ashraf Mohamed Ali Mashaly1, 2*, Ashraf Mohamed Ahmed1, 2, Mosa Abdullah AlAbdullah1, Mohamed Saleh AlKhalifa1 1 Department of Zoology, College of Science, King Saud University, PO. Box: 2455, Riyadh, 11451, Kingdom of Saudi Arabia 2 Department of Zoology, Faculty of Science, Minia University, El Minia, Egypt Abstract Ant species use branching networks of pheromone trails for orientation between nest and resources. The current study demonstrated that workers of the venomous samsum ant, Pachycondyla sennaarensis (Mayr) (Hymenoptera: Formicidae: Ponerinae), employ recruitment trail pheromones discharged from the Dufour’s gland. Secretions of other abdomen complex glands, as well as hindgut gland secretions, did not evoke trail following. The optimum concentration of trail pheromone was found to be 0.1 gland equivalent/40 cm trail. This concentration demonstrated effective longevity for about one hour. This study also showed that P. sennaarensis and Tapinoma simrothi each respond to the trail pheromones of the other species as well as their own. Keywords: Dufour gland, longevity, optimal dose, source, specificity Correspondence: * [email protected], *Corresponding author Received: 9 January 2010, Accepted: 21 February 2010 Copyright : This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed. ISSN: 1536-2442 | Vol. 11, Number 31 Cite this paper as: Mashaly AMA, Ahmed AM, Al-Abdullah MA, Al-Khalifa MS. 2011. The trail pheromone of the venomous samsum ant, Pachycondyla sennaarensis. Journal of Insect Science 11:31 available online: insectscience.org/11.31 Journal of Insect Science | www.insectscience.org 1 Journal of Insect Science: Vol. 11 | Article 31 Mashaly et al. Introduction Hölldobler and Traniello (1980) discovered that both a surface pheromone and tactile The study of insect pheromones has stimuli permit the formation of a demonstrated their pivotal roles in social communication bond between the two organization, recognition, mate choice, individuals of a tandem running pair. aggregation, and territoriality (Wyatt 2003). Pheromone trails illustrate how insect The samsum ant, Pachycondyla sennaarensis behavior is modulated by pheromones. (Mayr) (Hymenoptera: Formicidae: Foraging insects use pheromone trails to lead Ponerinae), is the most common ant in colony members to food sources and new nest savannah regions of Sudan (Levieux and locations (Horn 1976). In trail Diomande 1978). It has been recorded in communication, already excited individuals Saudi Arabia (Collingwood 1985), Kuwait, are led along a trail to the target area Oman, and Yemen (Collingwood and Agosti (Hölldobler and Wilson 1990; Traniello and 1996), in the United Arab Emirates Robson 1995). This pheromonal (Collingwood et al. 1997), in Iran communication system is based on the release (Akbarzadeh et al. 2004; Tirgari and Paknia of chemicals from a variety of specialized 2005) as well as many locations in Africa glands that then form a trail (Morgan 1990). (Taylor 2005). In Saudi Arabia it has established itself in both urban and rural areas In ants, different recruitment mechanisms and is closely related to the human activity include tandem running in which the scout ant sites. The ants seemed to have adapted to the leads one nest mate to the resource, group hot and dry weather of Riyadh Region recruitment which recruits tens of nest mates, especially in spring and summer by and mass communication which uses establishing the nests in moist sand in pheromones to recruit large numbers of nest irrigated gardens, parks, housing areas and mates (Wyatt 2003). Which recruitment roadside plantations (Al-Khalifa et al. 2010). mechanism is used depends as much on the Because of their ability to sting, these ants ecology of the species as its taxonomic have medical importance (Tirgari et al. 2004) position. Comparing closely related species and are considered as a significant public with different foraging strategies reveals that health hazard in Saudi Arabia (Al-Anazi et al. key factors that select for recruitment 2009). It has been described as unique among behavior are clumped, patchy food resources ponerines in its seed-eating habits (Lachaud (Traniello and Robson 1995). For example, and Dejean 1994). the ant Pachycondyla obscuricornis hunts small arthropods, and it has no need for This study was conducted for three reasons: foraging recruitment as each prey item can be first, the widespread distribution of this carried back to the nest by the finder. species in Saudi Arabia; secondly, its threat as However, for nest moving this species does a health problem in that it may cause use tandem running, facilitated by pygidial anaphylaxis in sensitive persons and even lead gland pheromones (Hölldobler et al. 1978; to death (Al-Shahwan et al. 2006); and third, Kugler 1978). In the tandem running trail pheromones have never been investigated recruitment technique in the ponerine ant, P. in this species. The current study investigates tesserinoda, Maschwitz et al. (1974) and the role of trail pheromone in the behavior of Journal of Insect Science | www.insectscience.org 2 Journal of Insect Science: Vol. 11 | Article 31 Mashaly et al. P. sennaarensis, including the glandular (500) workers originated from a different origin, optimal concentration, longevity, and colony. specificity of the trail pheromone. Each nest was connected to a foraging arena Materials and Methods with a sand-covered floor (2 cm thick). The ants were allowed to reach the arena by means Insects of two cardboard bridges (each with 1cm wide Colonies of P. sennaarensis (containing and 40cm long). The bridges originated close 1500–2500 workers, with brood of all stages to the nest entrance hole and diverged at and multiple queens (5–10), were collected approximately 30°, thus forming a V-shaped from Al Ehsaa Governorate, East Riyadh, and double bridge that connected to the arena at the Kingdom of Saudi Arabia. Collected nests two points approximately 15 cm apart. Source were moved to the ant insectary in the glands were ground in a small glass tissue Zoology Department, College of Sciences, grinder in 100 !l hexane and were drawn King Saud University. Ants were housed in along one branch of the V-bridge, using a 0.8 plastic nest-bottles within a large plastic box mm Standard graph pen (Standardgraph (45 x 30 x 18 cm) that was used as a foraging Zeichentechnik GmbH, area. Fluon-coated walls prevented ant escape. www.standardgraph.de). As control, The insectary was maintained at 28 ± 1º C, ~ equivalent amounts of hexane were used as a 30% RH, and 12:12 L:D. Ants were allowed trail on the other side of the V-bridge. After to access fresh water and sugar syrup in glass the solvent had evaporated (30 seconds post- tubes blocked with cotton wool, fed daily with application), both test and control trails were mealworm larvae, and weekly with apple placed simultaneously at the ant nest entrance. sauce. Ten days prior to the start of the At the end of the test, ants that entered the experiment and during the experiment, ants arena through the openings of the treated and were not given sugar sources to ensure that control bridges were counted. Each test was they would readily form foraging trails to the conducted five times and the activity was sugar syrup feeder. To prevent drying up nests calculated as the mean number of responding were moistened by adding a few drops of ants. Each V-bridge was used only once in an water when needed. experiment and at least 30 min elapsed between subsequent trail tests, but in each Trail pheromone experiments case the test group was tested only once each The determination of the origin of the trail day. After each test all ants were returned pheromones involved bioassay studies in back to their respective nests. Before and after which suspensions of the potential organ each test, the Standard graph pen was cleaned sources were presented to the ants via thoroughly with hexane. The last washing was artificial trails. The following organs were used in a blank trail test to ensure there was tested: pygidial, poison, Dufour’s glands, and no residual activity from the last test. As a hindgut. Experiments were carried out as negative control, a drawn circle made with a described in Hölldobler and Wilson (1970) pencil on the paper (with no chemical trail and Hölldobler (1976). Three experimental laid) was also presented to the ants to ensure groups (each 500 workers) were housed in that it no effect on the results.