Assessment of Seed-Borne Plant Pathogenic Fungi, Insect Emergence and Percentage Germinability Associated with Harvested and Stored Rice in Kwara State, Nigeria

This study was conducted to assess the incidence of seed-borne fungi, insect emergence as it affect the germinability rate of rice seed collected from the major rice growing areas of Kwara State, Nigeria, The rice seeds were collected during the dry season of 2019. Five (5) fungi species were isolated from all the rice samples. The incidence of fungi pathogens vary from one locality to another, as well as the frequency of occurrence. The pathogens isolated include Fusarium. oxysporium, Aspergillus spp., Aspergillus flavus, Aspergillus fumigatus., Cladosporium sp., Mucor sp. FARO 44 rice variety has the highest incidence of fungal pathogen(12.5× 104) while local varieties Alhaji Sule and Kuddo has the lowest incidence of (0.5× 104) respectively. Penicillium sp. has the highest percentage frequency of occurrence (49.3%) while cladosporium sp has lowest (1.33%) across all samples. Sample 9(F-52), 15(E) and 17(K) has the lowest percentage germinability of 41, 40 and 45% while sample 11(AB) and 8(K) has the highest percentage germinability of 84% and 77% respectively. All the samples do not have the most serious damaging insect infestation of Sitophilus oryzae but some of the sample has infestation of some other insects such as Rhyzopertha dominca, a lesser grain borer and a primary stored pest of cereals, Tribolium. castaneum a secondary pest and some other unidentified insects in varying percentage. Measures such as lowest moisture content of seed meant for storage and proper cleaning of the store must be put in place to avoid seed deterioration as a result of seed borne fungal pathogen and insect infestation.

Dependence of an aquatic insect population on contemporaneous primary production

Characterizing the dynamics of energy flow through ecosystems requires quantifying the degree to which primary and secondary production are coupled. This coupling is expected to be tight in ecosystems with high internal production relative to external carbon and energy inputs. We experimentally quantified the dependence of aquatic insect emergence on fresh primary production, specifically for the midge population in Lake Myvatn, Iceland. Using field mesocosms, we manipulated algal primary production by reducing light availability via shading. We then used dissolved oxygen incubations to estimate fluxes of carbon through photosynthesis (i.e., gross primary production or "GPP") over the course of the experiment. We found that elevated GPP was associated with higher emergence rates of adults, as judged both by comparison of emergence across the experimental shading treatments and estimates of in situ GPP within the mesocosms. Furthermore, larger adults emerged earlier than smaller ones, suggesting that asymmetries in resource availability among individuals affected the timing of emergence. Nonetheless, midge emergence was substantial under light-limiting conditions, indicating that while midges benefit from primary production contemporaneous with larval development, they are also capable of completing their life cycles on carbon already existing in the organic matter pool. Our results show that even in systems with limited allochthonous inputs, contemporaneous primary production may be not necessary for high secondary production and insect emergence. Instead, consumers can develop from consumption of biomass derived from past autochthonous primary production. This suggests that primary production and consumer dynamics can be partially decoupled in time in systems that depend on internal production.

Evidence of parthenogenetic populations from the Paratanytarsus laccophilus species group (Diptera: Chironomidae) in the Alaskan Arctic

Parthenogenesis, reproduction without fertilization, is not common in the Chironomidae (Diptera), a family of insects with more than 6,000 described species. Nonetheless, parthenogenetic species and strains have been documented in at least three subfamilies (the Chironominae, Orthocladiinae, and Telmatogoninae), spanning 17 genera and ~30 species. One such species, Paratanytarsus laccophilus Edwards 1929, is known to be parthenogenetic in a small portion of its range in Finland, with most other European populations of this species showing evidence of sexual reproduction. We present evidence of parthenogenetic populations from the Paratanytarsus laccophilus species group in the Nearctic, specifically a High Arctic site near Utqiaġvik (formerly Barrow), Alaska. During May-July of 2015 and 2016, we sampled emerging adult chironomids and pupal exuviae daily to document insect emergence phenologies. Across 15 local populations, all 623 pupal exuviae collected from the P. laccophilus species group were female. Larvae reared from two populations under controlled temperature treatments emerged as female adults (N=37). When isolated, these reared female adults oviposited, and eggs hatched successfully. These progeny were reared for another 12-13 days, reaching second instar larvae when they were preserved at the end of our field season. Taken together, this evidence strongly indicates parthenogenesis from the P. laccophilus species group at this location. This species was not previously documented at Utqiaġvik. Although parthenogenetic, their emergence at this location was highly synchronized. In the harsh environment of arctic Alaska, the fitness rewards of parthenogenesis are likely great. Indeed, chironomid parthenogenesis in the northern hemisphere is most commonly documented from far-northern extremes and in extreme habitats.

Asosiasi Lalat Buah (Bactrocera spp.) (Diptera : Tephritidae) dan Parasitoidnya pada Tanaman Jambu Biji Kristal (Psidium guajava L.) yang Dibudidayakan di Bali

Association of Fruit Flies (Bactrocera spp.) (Diptera: Tephritidae) and Their Parasitoid on Guava (Psidium guajava L.) Cultivated in Bali. The study on the association of fruit flies (Bactrocera spp.) (Diptera: Tephritidae) and their parasitoid on guava (Psidium guajava L.) cultivated in Bali was conduted in order to know the abundance, attacks percentage and the species of parasitoid associated on guava, cultivated in Bali. The sampling was done intentionally by taking attacked fruit in Musi Village, Buleleng Regency; Pelaga Village, Badung Regency; and Tiga Village, Bangli Regency. The results showed that 3 species of fruit flies were found, namely B. carambolae, B. papayae and B. albistrigata. The percentage and number of adult insect emergence in Musi Village were B. papayae (50.87% ; 2772 imago), B. carambolae (35.18% ; 1803 imago) and B. albistrigata (13.94% ; 741 imago). In Pelaga Village B. carambolae (61.31% ; 2864 imago) dominates and B. papayae only 38.69% and 1801 imago. B. carambolae is also found dominant in Tiga Village (59.08% ; 2303 imago) and B. papayae only 40.92% and 1603 imago. Percentage of damage to guava is 24.27% on average. There are three species of parasitoids found that are associated with fruit flies on guava in Bali, namely Fopius arisanus, Diachasmimorpha sp. and Opius sp. The average parasitic rate is 6.76%. The highest parasitic rate is in Musi Village, Buleleng while the lowest is in Tiga Village, Bangli.

Effects of Stream Temperature and Substrate Type on Emergence Patterns of Plecoptera and Trichoptera From Northeastern United States Headwater Streams

The timing and spatial distribution of aquatic insect emergence is linked to the abiotic and biotic environment in streams. Studies of aquatic insect emergence are needed to generate baseline data to identify potential shifts in phenology and habitat-related emergence with global change. The purpose of this study was to 1) compare the timing of Plecoptera (stonefly) species emergence between two streams with different thermal regimes and 2) characterize the distribution of emerging Plecoptera and Trichoptera (caddisflies) from wood, rock, gravel, and sand substrates in five forested, headwater streams. Emergence timing and duration varied among Plecoptera species, with Ostrocerca albidipennis (Walker) (Plecoptera: Nemouridae) emerging only in May and four species in the genus Leuctra (Plecoptera: Leuctridae) collectively emerging throughout the summer (May to September). We observed earlier emergence of Amphinemura nigritta (Provancher) (Plecoptera: Nemouridae) and a longer total emergence period for Leuctra ferruginea (Walker) (Plecoptera: Leuctridae) in the stream with ~1.5°C warmer temperatures, which suggested that some insects may experience phenological shifts in streams with subtle differences in temperature. The abundance of plecopteran and trichopteran taxa emerging from wood was generally greater than for gravel or sand, and sand was the least preferred emergence substrate. The results suggest that human actions that decrease large wood and increase fine sedimentation may decrease habitat quality for many insect larvae and limit preferred emergence substrates.