Termites are one of the social insects living in large colonies that can cause economic loss. The objective of this study was to estimate foraging territory of infested subterranean termites on building structure. A mark-recapture study was conducted on eight Coptotermes gestroi colonies located at selected infested building structures in Penang, Malaysia. From the foraging study, the population of C. gestroi was estimated to be within the range of 106,592±6,968 to 4,185,000±2,127,328. Additionally, the foraging territory was from 13 to 300 m2 of the infested building structures. Meanwhile the maximum foraging distance was from 4 to 30 m of the infested structures. The results indicated that each of the building structures was infested by a single colony. This study also showed that the triple mark recapture technique used to estimate the population size of the termite colony was capable of providing rough estimates of foraging population of C. gestroi.
Kerengga (Oecophylla smaragdina) adalah satu komuniti serangga yang penting di kanopi pokok. Walau bagaimanapun, kajian tentang aktiviti pencarian makanan kerengga adalah terhad. Oleh sebab itu, satu kajian lapangan dijalankan untuk mengkaji pemilihan makanan dan aktiviti pencarian makanan oleh semut ini dijalankan selama tiga hari. Pemilihan makanan oleh kerengga ini dikaji dengan menggunakan tiga jenis makanan (tuna, kulit ayam, dan susu tepung) yang mengandungi protein, lipid, dan karbohidrat. Aktiviti pencarian makanan dikaji berdasarkan dua parameter iaitu suhu persekitaran dan kelembapan relatif yang direkod sepanjang tempoh experimen. Keputusan experimen menunjukkan O. smaragdina lebih menggemari makanan berprotein berbanding makanan berlipid dan berkabohidrat, serta aktiviti pencarian makanan dipengaruhi oleh suhu persekitaran dan kelembapan relatif. Hasil kajian ini menunjukkan bagaimana kerengga bertindak balas terhadap tiga jenis makanan yang berbeza dan secara tidak langsung, menunjukkan aktiviti pencarian makanan yang strategik untuk memaksimumkan bekalan makanan kepada koloni mereka.
Chironomus javanus (Kieffer) and Chironomus kiiensis Tokunaga were redescribed from materials collected from a rice field in Pulau Pinang, Malaysia. The larvae can only be distinguished after careful preparation and examination using a compound microscope, but the pupae were not useful to differentiate C. javanus from C. kiiensis. The adult specimens showed clear body and wing characteristics for rapid and accurate identification.
The importance of terrestrial insects as food items for freshwater fish was studied by examining stomach contents of Devario regina (Fowler 1934) and its population parameters at canopied areas of selected tributaries of Kerian River, in the northern state of Peninsular Malaysia. Ninety six percent (121 out of 126) of the fish stomachs examined contained food materials in the stomachs and the values of percentage of occurrence (%F), percentage numerical (%N) and percentage points (%P) indicated that collected fish ate similar food items in all rivers. Among the food categories, scavenging terrestrial ants (Formicidae) were the most dominant food item, hence the main diet for this species. The Index of Relative Importance (IRI) scores of food items indicated that ants were higher than other food items. This surface water feeder experienced a positive allometric growth (W = aLb) with a b (rate of growth) value of 3.256. Its asymptotic length, growth constant and growth performance index represented this species with a short life-span (L∞ = 10.90 cm, K = 1.20 year-1, φ’ = 2.15, tmax = 3 year, respectively) and had higher natural mortality (M = 2.40 year-1) than fishing mortality (F = 0.35 year-1) while the fish stock was underexploited (E = 0.13). The finding of this study indicated the importance of terrestrial ants as a food source that support excellent growth of D. regina and the need to conserve riparian trees along river banks to provide allocthonous materials and habitats for the ants.
The diversity and abundance of macroinvertebrate shredders were investigated in 52 forested streams (local scale) from nine catchments (regional scale) covering a large area of peninsular Malaysia. A total of 10,642 individuals of aquatic macroinvertebrates were collected, of which 18.22% were shredders. Biodiversity of shredders was described by alpha (αaverage), beta (β) and gamma diversity (γ) measures. We found high diversity and abundance of shredders in all catchments, represented by 1,939 individuals (range 6-115 and average per site of 37.29±3.48 SE) from 31 taxa with 2-13 taxa per site (αaverage=6.98±0.33 SE) and 10-15 taxa per catchment (γ=13.33±0.55 SE). At the local scale, water temperature, stream width, depth and altitude were correlated significantly with diversity (Adj-R2=0.205). Meanwhile, dissolved oxygen, stream velocity, water temperature, stream width and altitude were correlated to shredder abundance (Adj-R2=0.242). At regional scale, however, water temperature was correlated negatively with β and γ diversity (r2=0.161 and 0.237, respectively) as well as abundance of shredders (r2=0.235). Canopy cover was correlated positively with β diversity (r2=0.378) and abundance (r2=0.266), meanwhile altitude was correlated positively with β (quadratic: r2=0.175), γ diversity (quadratic: r2=0.848) as well as abundance (quadratic: r2=0.299). The present study is considered as the first report describing the biodiversity and abundance of shredders in forested headwater streams across a large spatial scale in peninsular Malaysia. We concluded that water temperature has a negative effect while altitude showed a positive relationship with diversity and abundance of shredders. However, it was difficult to detect an influence of canopy cover on shredder diversity.