In the present study, body length and dispersal ability were examined in carabid beetles (Coleoptera: Carabidae) sampled in the Peruvian Andes along two altitudinal gradients: old-growth forest and anthropogenically disturbed region. Dispersal ability was estimated by the flight-wing condition (i.e. macropterous or brachypterous) and the cuticular length of the flight muscle (medial length of the metasternum). The relationship between body length and altitude for combined gradients varied by tribe; all possible relationships were found: positive; negative; no relationship. At the family level, a negative relationship between altitude and insect body length was found; this was predicted because of a decrease in the diversity of resources, habitat area and primary productivity, and the increase in the unfavourable environment observed at high altitudes. Flight muscle length was also highly variable among tribes; however, for combined gradients, a negative correlation with altitude was found at the family level. Some tribes were either completely macropterous or brachypterous, but at the family level, the percentage of brachyptery increased with altitude. We suggest two hypotheses that may explain the increased incidence of flightlessness observed with increasing altitude: constraints of energy use and reduced need for dispersal potential. At the family level, carabid beetles tended to have a greater body length and decreased brachyptery in disturbed regions compared with old-growth forests. Increased dispersal ability was expected because of the need to find a suitable habitat in disturbed areas. Observed relationships may depend upon which tribes are examined and whether the forest on an altitudinal gradient has been disturbed.

Pest control strategies against Helicoverpa armigera (Hübner) using protease inhibitors have relied on the gut protease profile of the later larval stages of the insect, with serine proteases being considered predominant. Little is known about the gut protease profile of early larval instars. Therefore, the aim of the present study was to detect the levels of gut protease activities in the third-, fourth-, fifth- and late fifth-instar larvae of H. armigera reared on an artificial diet using specific substrates and inhibitors. The analysis of the gut protease profiles of different instars revealed different levels of protease activities at different instar stages. Significant variations were also observed in the specific activities of trypsin, chymotrypsin, cysteine protease, carboxypeptidase-A and aminopeptidase-N across the instars. In general, the activities of the proteases increased from the third to the fifth instar and then decreased at the onset of pupation in the late fifth instar. Proteolytic activity was optimal at pH 12 for gut extracts from the third-, fourth- and fifth-instar larvae. Bioassays with phenylmethylsulphonyl fluoride (PMSF), a serine–cysteine protease inhibitor, revealed high mortality, and that with sodium ethylenediaminetetraacetic acid (EDTA-Na), a metalloprotease inhibitor, also showed retarded larval growth. The inhibition induced by 0.05% PMSF and 0.05% EDTA-Na in combination was similar to that induced by 0.1% PMSF alone.

Leptocybe invasa Fisher & La Salle was first recorded several years ago in Sri Lanka in the Eucalyptus camaldulensis Dehnh. plantation in Maragamuwa. Recent observations have revealed a decrease in gall infestation, and the present study was conducted to investigate the biology of L. invasa, its damage to E. camaldulensis and the presence of any natural enemies. Life-cycle duration, developmental stages and activity patterns were investigated. The abundance of gall wasps was monitored using sticky traps. Damage caused to different stages of coppices was also assessed. The damage index was calculated from the percentage of leaves affected in each coppice. Insects were reared from the galled coppices, brought to the laboratory, identified and counted. The life-cycle duration of L. invasa was 132 days on average. The damage index was low throughout the study period. Leptocybe invasa attacked the coppices of E. camaldulensis when they turned green in colour; damage increased as the coppices developed until maturity. Four species of parasitoid wasps were reared from the leaf and shoot galls. Megastigmus sp. was the most abundant parasitoid; the mean percentage of parasitization was 67.00 ± 8.00. Natural enemies of L. invasa might have contributed to the decrease in gall infestation observed recently in the coppices of E. camaldulensis in the study site.

In the present study, the susceptibility of different developmental stages (eggs, larvae, protonymphs, deutonymphs and adults) of Tetranychus urticae Koch to the entomopathogenic fungi Beauveria bassiana (Balsamo-Crivelli) Vuillemin and Metarhizium anisopliae (Metchnikoff) Sorokin was evaluated in the laboratory. At each developmental stage, four concentrations (3 × 105, 1 × 106, 3 × 106 and 1 × 107 conidia/ml) of both fungi were sprayed. Egg viability and motile-stage mortality varied among the fungal isolates and conidial concentrations. The highest conidial concentration (1 × 107 conidia/ml) significantly reduced the viability of eggs and increased the mortality of motile stages. However, deutonymphs and adults were more susceptible to fungal infection than larvae and protonymphs. The lethal concentration values to 50% (LC50) and 90% mortality (LC90) varied with the fungal isolates and developmental stages. The results show the prospects of B. bassiana and M. anisopliae for the control of T. urticae.

In the present study, experiments were carried out in French bean fields over two planting periods to evaluate the potential use of sticky traps for monitoring the populations of pest thrips. To this end, blue, yellow and clear sticky traps (with and without a thrips lure, i.e. Lurem-TR) were tested. Field observations on thrips catches were made at weekly intervals from the sticky traps, and absolute estimates of thrips populations and their natural enemies were made by destructive (picking leaves and flowers) and non-destructive sampling (plant tapping) of plants until crop senescence during the two planting periods. Blue traps caught two and three times more thrips compared with yellow traps over the first and second planting periods, respectively. Blue traps were more attractive to Megalurothrips sjostedti (Trybom), Frankliniella schultzei (Trybom) and Frankliniella occidentalis (Pergande), while yellow traps were only attractive to Hydatothrips adolfifriderici (Karny) and the natural enemies of thrips. The addition of Lurem-TR to the sticky traps significantly increased the capture of all thrips species, but not their natural enemies. The estimates of thrips populations from blue sticky traps with Lurem-TR were found to be highly correlated (r= 0.95; P< 0.001) with the absolute estimates of thrips using the destructive sampling method. The results demonstrate that blue sticky traps and Lurem-TR can be an efficient tool for the monitoring of thrips populations on French beans with least influence on their natural enemies.

The larval haemolymph of three cyclorrhaphous dipteran flies, Sarcophaga ruficornis Fab., Musca domestica L. and Chrysomya megacephala Fab., possesses five different types of haemocytes: prohaemocytes; plasmatocytes; granulocytes; spherulocytes; oenocytoids. In addition, vermicytes are found in the haemolymph of S.ruficornis and adipohaemocytes in the haemolymph of M. domestica. The total haemocyte counts in the three dipteran flies show an increasing trend throughout the larval stage, attaining a peak value in the freshly formed white puparium stage and declining thereafter. The differential haemocyte count shows a decline in the number of prohaemocytes with an increase in the number of plasmatocytes, granulocytes and spherulocytes.

Helopeltis theivora Waterhouse is a major sucking pest of tea in northeast India. No effective predators or parasitoids have been recorded from the field, and, therefore, insecticides play a significant role in the control of this pest. Potassium is known to impart physiological resistance to plants against sucking pests. The present study conducted two field trials to evaluate the bioefficacy of thiamethoxam 25 WG and bifenthrin 8 SC applied alone at the dosage recommended by the Tocklai Tea Research Institute and in combination with 2% potassium chloride (KCl) and mined potassium sulphate (K2SO4) against H. theivora. No phytotoxic effects were observed in the field when tea bushes were sprayed. The control of H. theivora achieved by the combinations of thiamethoxam+KCl/K2SO4 and bifenthrin+KCl/K2SO4 was found to be statistically significant (P< 0.05) compared with the sole application of the insecticides. These treatments could be included in the current integrated pest management programme against H. theivora.