Objectives To describe wasp and bee species that sting humans, analyse risk factors and clinical features.

Dengue vector control programmes are mainly focused on insecticide fogging/space spraying to control adult Aedes mosquito vector populations. Due to the diurnal habit of the vectors, spraying is routinely conducted during the day when many other insect species are also active. This study reports the simultaneous effect of fogging on non-target insects by direct counting of knockdown in the insect population. Eight fogging treatments were conducted in two sites in Kurunegala District of Sri Lanka. Pesguard insecticide was sprayed in each treatment for 8 minutes according to the standard methodology and the ‘knockdown insects’ were collected on randomly spread polyethythene sheets (10 m2). A total of 3884 insects (24.3 insects per treatment per m2) belonging to 12 orders were collected and 12.44% of them recovered during a 24-hr recovery period. Diptera was the most affected insect order (36%) followed by Collembola (30%) and Thysanoptera (17%). Out of the 31 mosquitoes (<1%) collected, only two (<0.1%) belonged to the genus Aedes. Body length of 93% of the affected insects ranged from 0.35 mm to 1.8 mm. Positive controls using the WHO standard cage bioassays with the mosquito Ae. albopictus (n = 417) and the stingless bee Trigona iridipennis (n = 122) showed 100% initial knockdown, and 83.5% mosquito and 93.5% bee mortalities after the recovery period. The study shows that insecticide fogging does have a severe effect on non-target insects such as pollinators; therefore, fogging operations should be done in a controlled manner and indiscriminate fogging should be avoided.

Studies to evaluate consequences of native species showing invasive behaviour are rather scarce in the tropics. Bambusa bambos (L.) Voss., a native bamboo species, expands populations in its native range causing changes to the appearance of forests in dry and intermediate zones of Sri Lanka. The study evaluated the impacts of B. bambos spread in Tropical Moist Evergreen Forests (TMEFs) in Sri Lanka. A vegetation study was carried out in forest patches with and without bamboo (B+ and B-) from three study sites viz., Galboda (GAL), Moragolla (MOR) and Maragomuwa (MAR) located in the Intermediate Zone of the island. Six 100 m 2 quadrats were eramarked at different distances from the forest edge towards the forest interior along three transects in each B+ and B-forest communities per site totaling 108 quadrats (2 forest communities B+ and B-× 3 transects × 6 distances × 3 sites = 108). Due to high site-specific differences, the results were analyzed and presented site-wise. Of the total of 127 species, 35 (27.6%) and 20 (15.7%) species were exclusively found in B+ and B-, respectively. The endemics were constantly more abundant in bamboo-free forest patches. The analyses also revealed a high dissimilarity of species compositions between B+ and B-forest communities. The mortality incidences were significantly greater in bamboo-forests, possibly due to frequent fires aided by high accumulation of light bamboo litter. Despite no consistent differences between B+ and B-communities in all study sites due to high heterogeneity, the results indicate that B. bambos has shown the potential to alter the composition and structure of these native forests through bamboo-driven modifications to micro-environmental conditions of these forests. Thus, the study highlights the importance of more comprehensive studies to explore long-term impacts of B. bambos in native forests in the region and to introduce measures to mitigate some of these negative impacts. The underlying causes of high mortality incidences should also be further investigated as it may leads to the decline of the quality of these native forests.

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This study compares the termite assemblages in a natural and a secondary forest located at two different elevations in the Hantane hills, a tropical evergreen forest in mid country Sri Lanka, with a view to identify their distinctiveness. To sample the termites in the two forest types the belt transect method was used supplemented by random collections. A total of 11 species of termites in four genera belonging to three subfamilies and one family, Termitidae were recorded; nine species from the secondary forest and two species from the natural forest. The two species, Ceylonitermellus hantanae and Dicuspiditermes incola showed a distinct distribution in being confined only to the natural forest at high elevation. Termites recorded were put into feeding groups based on their taxonomic identity. Termites of the natural forest were found to be exclusively true soil feeders. Those of the secondary forest were wood feeders; either fungus growing (8 spp.) or non-fungus growing wood feeders (1 sp.). The high abundance and low diversity of the natural forest termite species in comparison to secondary forest species also make them distinct. Elevation, climate, vegetation, ground cover and the degree of human interference appear to contribute to the distinctiveness of termite assemblages in the two forests types reported here.