Life table and demographic parameters of rice leaffolder, Cnaphalocrocis medinalis guenee (Lepidoptera: Pyralidae)

Rice leaffolder, Cnaphalocrocis medinalis is important pest species and become a major threat to rice production in many Asian countries including Malaysia. A range of 30 to 80% of rice yield losses was assessed from severely damage fields under epidemic situation in India. Cnaphalocrocis medinalis has history of outbreak in Sekinchan, Selangor in early 1980’s. Understanding the biology and factors that could be manipulated for its control are very limited. Life table and demographic parameters play important role in determining the key factors that responsible for the highest mortality within population. Therefore, the objective of our study was to construct life table and demographic parameters of C. medinalis. A survivorship and fecundity study of C. medinalis was conducted in laboratory (27.2±0.48 °C, 78.4±1.64% RH and 12:12h photoperiod) using three cohorts consisted of 102, 103 and 105 one-day old eggs. The survival and mortality of every life stage were observed and recorded daily. Nine pairs of one-day old C. medinalis adults were used in fecundity study. The laid eggs were observed daily and longevity of adults were recorded. Standard life table parameters and population age structures were calculated from daily records of survival, mortality and fecundity of each cohort. Two-sample t-test was performed in comparing of longevity between adult male and female. The highest mortality was recorded in first instar larvae (22.58%) with K-value of 0.125 indicated that this stage is the key factor in regulating C. medinalis population. A total of 32.26% individuals has successfully reached at adult stage with average sex ratio was 0.96:1.00 (Female: Male). The emergence of first female was on day 28 whilst the last female died on day 43. The earliest egg was laid on day 30 and continued until day 35 with maximum oviposition was on day 31 and 32 which constitute 57.04% of total eggs. The female lived for about 7.56±0.38 days with fecundity of 104.33±5.43 eggs. The intrinsic rate of natural increase (rm) was 0.08 per female per day with mean generation time (Tc) of 31.56 days and doubling time (DT) of 8.19days. This shows that C. medinalis population has increased and build up rapidly in short time period. Our results suggested that the control program should be done during early stage of larvae in order to suppress the C. medinalis population effectively. Life table study of C. medinalis on other local rice varieties should be conducted in determining its survivorship and reproduction on other host varieties

Population Fluctuation of Rice Leaffolder, (Cnaphalocrocis medinalis) in Two Consecutive Rice Seasons

Larvae of rice leaffolder, Cnaphalocrocis medinalis attack rice crop at all three phases (from tillering until maturity stages). Their population throughout season was influenced by abiotic and biotic factors. Study on population fluctuation is important to understand the population dynamic and its factors in natural field condition. Thus, a study of population fluctuation of C. medinalis was conducted at rice field in Semanggol, Perak. Larvae were collected from 10 rice hills per plot in three 15 m x 4 m plots started on April 5, 2015 until June 7, 2015 (off season) and from October 25, 2015 until December 27, 2015 (main season). Abiotic data namely temperature, relative humidity (RH) and rainfall were obtained from Department of Meteorology Malaysia. Comparison of C. medinalis population between two seasons at different weeks was analysed using two-way ANOVA. The relationship of C. medinalis population with abiotic factors was analysed using Pearson correlation and stepwise regression. There was a significant interaction effect between season and week (F9,40=2.19; p<0.05). The highest population was recorded at week 55 day after transplanting (DAT) in main season comprised of 17% of total collection, followed by week 62 in off season (14%), week 48-main season (13%) and week 55-off season (13%). There was a positive correlation between C. medinalis population and RH in main and off season with RH was the key factor in regulating population in both seasons. Our results revealed that population of C. medinalis at different weeks was influenced by season. It is due to differences of weather condition between seasons, management practices and plant stages. The highest population recorded during reproductive phase is due to the morphology of rice plant that offers great suitability for larvae feeding and development. The abiotic factors also influenced C. medinalis population. Therefore, the abiotic factors should be considered in management of C. medinalis besides the plant stage and fertilizer effect. Future research on effect of natural enemies on C. medinalis population in field is needed in order to gain a better understanding of the factors that influence the population

Diversity and abundance of storage pest in rice warehouses in Klang, Selangor, Malaysia

Insect’s pest infestation on rice product cause a serious damage either in quantitative or qualitative aspect. This paper assesses the abundance and diversity of insects pest of stored products in rice warehouses, through a study in three rice warehouse (Jasa, Tenggara, Target Lane) in Klang Selangor, Malaysia. Investigations recorded four main insect species in all the warehouses are Oryzaephilus surinamensis, Tribolium castaneum, Sitophilus oryzae and Cadra cautella. Oryzaephilus surinamensis showed the highest abundance in all warehouse with total 47403 individuals (97%), T. castaneum with 431 individuals (0.88%), C. cautella with 760 individuals (1.56%) and S. oryzae with the lowest abundance (11 individuals; 0.02%). The Shannon-Weiner index shows that highest insects diversity was in Tenggara warehouse (Shannon’s, H’ = 0.28), while Target Lane were the lowest (Shannon’s, H’=0.11). The information on insect’s pest diversity in rice warehouses is very useful to implementation of management and controlling insect’s pest infestation in stored rice grains

The effect of elevated co2 on life cycle of Tenebrio molitor L. (COLEOPTERA: TENEBRIONIDAE)

Tenebrio molitor L. (Coleoptera: Tenebrionidae) is a major pest of storage products and popularly used as a model species in biological research. This research is crucial in demonstrating the effects of increased CO2 in the environment. The objective of this study was to determine the effect of life cycle of T. molitor (F1) at two significance systems of CO2 namely Free Air CO2 Enrichment System (FACE) and Open Roof Ventilation Greenhouse System (ORVS). Each stage of T. molitor from 10 transparent plastic containers was observed every 2 days and recorded. Prolonged of complete life cycle on the T. molitor in ORVS (147-172days) observed with 43% delayed compared to FACE (71-84 days) and rearing room as control (RR) (77-105 days). The extension was due to prolong of larval to pupal development in ORVS (141-154 days), however, only 77-84 days in RR and FACE (71-84 days). The description of morphological changes in all stages and its coloration also recorded. This preliminary findings are important in predicting the T. molitor survivability due to climate variability and in strategizing the Integrated Pest Management (IPM) in the warehouses of storage products

Termite associated to oil palm stands in three types of soils in Ladang Endau Rompin, Pahang, Malaysia

Termites are found in various habitats, particularly diverse communities occurring in tropical forest and peatlands. Termites are beneficial insects, which function as soil engineers, improving the soil quality. However, in peatlands converted to commercial oil palm plantations, they are considered as pests. There is lack of studies on termite communities in converted peatlands in Peninsular Malaysia. Thus, this study investigated termite species associated with oil palm stands in three soil types (clay, shallow peat and deep peat) in Endau Rompin Plantation. The stand scouting method was used to record the numbers and types of termites associated with palm trees in the individual stands on different soil types. A total of 29 termite species associated with the palm stands were identified morphologically. All the species belonged to the families Rhinotermitidae and Termitidae. Twenty-three of the 29 species were found in the shallow peat, 16 in clay soil and 15 in deep peat. The community structure was synthesized by two-way cluster analysis with Sorensen (Bray Curtis) distance measure. Five termite groups associated with two soil types (clay soil and shallow/deep peat) were generated. Moisture levels and organic content were likely to determine the presence of soil feeders identified in the presence study. This study provides information on the status of termite species in oil palm plantation areas. Such information may be useful in future planning strategies by the plantation management

Interaction of Predatory Ladybird Beetle, Micraspis discolor with Nilaparvata lugens throughout Paddy Growing Seasons

Coccinellidae is a high-interest family that has performed well and is widely distributed. It is valuable in economic service because it acts as an agricultural biological control agent. The Micraspis discolor (Syn=Verania) (Coleoptera: Coccinellidae) is a successful omnivorous predator in rice ecosystem and functions well as a general biological control for maintaining the population of brown planthopper (BPH) (Nilaparvata lugens), the major rice pest worldwide. Studies of natural enemies’ abundance are necessary to increase the practical use of biological control in agriculture. This study investigated the abundance correlation of M. discolor (prey) and rice pest N. lugens (prey) from two different geographical areas of rice fields in west and south Peninsular Malaysia. The cyclone lightrap and sweep net method succeeded in collecting 185 individuals of M. discolor and N. lugens. The study indicated that M. discolor, and the N. lugens collected from Selangor were more numerous than Johor in the ripening phase than in the reproductive and vegetative phases.  M. discolor can be found in all stages of rice growth. There are positive correlations between M. discolor and N. lugens in both localities throughout the rice growing season. The positive correlation highlighted that the number of pests has increased parallel to the number of predators and vice versa.  The use of M. discolor as a predator is essential in agriculture, along with the treatment of a healthy ecosystem landscape of diverse vegetation combinations, which helps to reduce the use of pesticides

Insect species composition in an under SRI management in Tanjung Karang, Selangor, Malaysia

The composition of the insect species during the mature stage of organic paddy fields in Tanjung Karang, Selangor, Malaysia, were investigated. All specimens were collected via three sampling methods namely sweep net, handpick and stem cut. The specimens collected were identified to the family level and when possible, to the species level. A total of 404 individuals were successfully identified from 19 families, viz. Cerambycidae, Coccinellidae (Micraspis discolor (Fabricius, 1798)). Anthomyiidae, Calliphoridae, Phoridae (Megaselia sp.), Platypezidae, Platystomatidae, Sciomyzidae, Sepsidae, Alydidae (Leptocorisa chinensis Dallas, 1852), Pentatomatidae (Scotinophara coarctata (Fabricius, 1798)), Delphacidae (Nilaparvata lugens (Stal, 1854)), Apoidae, Braconidae (Bracon hebetor Say, 1836) Ichneumonidae (Temelucha philippinensis Ashmead, 1904, Xanthopimpla sp.), Sphecidae, Trigonalidae, Pyralidae (Chilo polychrysa (Meyrick, 1932)) and Tettigoniidae. Additionally, two larval stages were identified molecularly based on COI sequences and resulted in 98% identical similarity to Chilo polychrysa using BOLD and BLAST analyses. Maximum parsimony (MP) analysis also clustered Chilo polychrysa in a monophyletic clade and was supported by a 99% bootstrap value. The abundance and composition of the dominant species collected are discussed. This is a fundamental study that investigated the diversity of insect species for future reference in insect pest management, especially in organic paddy fields

Fanning behavior of stingless bee, Heterotrigona itama (COCKERELL, 1918) (HYMENOPTERA: APIDAE)

The increase of temperature shows a negative impact on the behavior of the insects live in colonies, including the stingless bees. The stingless bees employ the fanning behavior as the best method to remove excess heat within colonies. The objective of this study was to investigate the fanning behavior of the Heterotrigona itama (Cockerell) in relation to regulate inner temperature and relative humidity. This study was conducted from January 2023 to May 2023 using three colonies. The fanning behavior of H. itama has been observed from 0800H until 1700H for 5 minutes per hour per 3 days for 5 months with camera recorder. There were significant differences between time and fanning behavior (F9,449 = 34.96, P>0.005) from 0800H to 1700H. In addition, the frequency of fanning behavior increased when the temperature hit on 28ºC±SD and stop when the temperature below 27ºC±SD and showed a significant difference (F70,449 = 42.59, P>0.005). Furthermore, changes of humidity also stimulate the fanning behavior of H. itama and showed a significant different (F41,449 = 36.83, P>0.05). Besides that, the fanning behavior started with aggregation of workers at the entrance and the leader site at the top of the entrance to stimulate other workers to fan the hives according to the changes of the temperature. The fanning behavior occurred during the hot season to reduce the temperature inside the colony, while stabilizing the humidity inside the colony during the raining seasons

Insect diversity and abundance during the crepuscular and nocturnal temporal periods in the Kota Gelanggi limestone complex, Pahang, Malaysia

The diversity and abundance patterns of nocturnal insect orders during the crepuscular and nocturnal periods, 6pm-9pm, 10pm-1am and 4am-7am at Kota Gelanggi limestone complexes were investigated. The insects were collected by using light traps over a period of six months from May to October 2014. A total of 35 732 individuals from 19 orders were captured. Coleoptera (n=14 103, 39.5%), Hymenoptera (n=10 030, 28.1%) and Diptera (n=4 821, 13.5%) were the most abundant orders. The results showed a bimodal pattern in the abundance of insects where more were caught during dusk followed by dawn and the lowest during the nocturnal period. However there was no significant difference (F= 0.71, df= 2, P> 0.05) in insect abundance between the three sessions. Studies on nocturnal insect activity patterns give us an understanding of the behaviour of the insects especially agricultural pest insects, and this information is necessary to develop effective pest control management

Ectoparasites (ticks and mites) prevalence on small to medium-sized mammals associated with habitat condition in Kemasul, Pahang

Ectoparasites of small mammals and medium mammals are divided into two main classes which are Insecta and Arachnida. The members of the class Arachnida including order Ixodida (ticks) and Mesostigmata (mites) meanwhile class Insecta comprising Phthiraptera (lice) and Siphonaptera (fleas). This study was conducted to determine tick’s and mite’s prevalence on the small to medium-sized mammals in Kemasul Forest Reserve, Pahang. This forest has undergone rapid deforestation for agricultural purposes. Two study sites were chosen which represented by a forest remnant surrounded with different matrix of monoculture plantation; Jambu Rias (JR) (Elaeis guineensis) and Chemomoi (CM) (Acacia mangium). Three hundred wired mesh cage traps sized (28 cm × 15 cm × 12.5 cm) and forty wired mesh cage traps sized (60 cm × 40 cm × 40 cm) were deployed at the study area and ectoparasites were extracted from each host using a fine comb. Identification was based on morphology and molecular using cytochrome oxidase 1 for confirmation. Mites only represented by Laelaps sp. which shows 95% and 70% prevalence in JR and CM respectively. Ticks were represented by five species, namely Ixodes granulatus, Dermacentor atrosignatus, Rhipicephalus sanguineus, Amblyomma testudinarium and Haemaphysalis sp. JR comprise of five species while CM with two species. I. granulatus was the most common infesting the small mammals in both sites. The highest parasite load was found on small mammals which were Maxomys surifer, M. rajah and M. whiteheadi in both study sites, particularly with mites. The study indicates that habitat condition significantly affects parasite prevalence in small to medium-sized mammal population, which could be due to the resilience of an individual to persist in disturbed habitat