The present study surveyed adult caddisflies in Ile-Ife to identify the species that contribute to the fauna of freshwater ecosystems of this area and to determine their seasonal abundance. Adult caddisflies were collected between June 2009 and November 2010 from eight sampling stations established at different locations using an improvised light trap. A total of 754 adult caddisflies that were collected represent six species in six genera and three families. The species identified are Dipseudopsis conformis Navas, 1931, Polymorphanisussimilis Ulmer, 1912, Aethaloptera dispar Brauer, 1875, Ceraclea njalaensis (Mosely, 1933), Pseudoneureclipsis mlangensis Mosely, 1939 and Cheumatopsyche digitata (Mosely, 1935). The Hydropsychidae was represented by three species belonging to three genera. The hydropsychid C. digitata was the dominant and most widely distributed species, occurring at all sampling stations with the highest frequency of occurrence (51%). On the other hand, P. mlangensis (Dipseudopsidae) was the least abundant with the lowest frequency of occurrence (0.8%).

In high-altitude summer pastures, horseflies (Diptera: Tabanidae) can be a serious nuisance to livestock, as well as mechanical vectors of animal diseases such as besnoitiosis, an enzootic disease in the Pyrenees. However, the activity of horseflies in mountainous environments is poorly documented. To study the seasonality and distribution of tabanids in the Pyrenees Mountains, a sampling design was set up in two valleys on opposite sides of the mountain, one north-facing and one south-facing, along high-elevation gradients and at different distances from a water body between May and October 2011. The influence of the landscape on species richness and abundance was assessed by taking into account forested and unforested areas in 200 m radii around the trapping sites. Our findings indicated that: (1) The slope, the altitude and the size of unforested patches significantly influenced community composition of tabanids. (2) Altitude had a positive or a negative effect, depending on the species. (3) Species richness and abundance were negatively correlated with large open habitats and positively correlated with patch-shape complexity. (4) Seasonal succession of the most abundant species was observed in both valleys, with a maximum of catches at the beginning of August; however, tabanid activity ended earlier in the southern valley, which was more exposed to sunlight. (5) Philipomyia aprica, Tabanus bromius, Tabanus glaucopis and Hybomitra auripila were active from 9:00 to 19:00 h (GMT+1), with a peak of activity at midday. This paper also discusses the implications of these findings in relation to changes in horsefly distribution and their control in mountainous environments.

A monospecific stand of the alien shrub Mimosa pigra (Mimosaceae) was examined weekly for 14 months from March 1984. A total of 44 phytophagous insect species were found on M. pigra. The five most abundant of these made up 74% of the total community. This insect community in general showed a distinct seasonal cycle of abundance with maximum numbers during the wet season. However, a few species had a completely different pattern.

Two species, Mictis profana (Hemiptera: Coreidae) and Platymopsis humeralis (Coleoptera: Cerambycidae), were observed to cause substantial damage to M. pigra. When compared with the fauna of M. pigra from its native region, Central America, that of the Northern Territory is low in leaf and flower-feeding insects. It is suggested that these types of insects be sought as future biocontrol agents to complement those native insects causing damage and those biocontrol agents already released.

A ‘rice garden’ with monthly plantings of rice was established in an irrigated lowland area in April 1993 and continued for 3 years. Populations of the most common insects, the stalk-eyed flies, Diopsis spp., and the green leafhoppers, Nephotettix spp., and spiders and stemborer damage varied distinctly in relation to month of transplanting. Arthropod populations also exhibited distinct patterns in relation to crop growth stage. Grain yields varied with month of transplanting but there was no distinct trend from one year to the next. This study indicated that continuous cropping of the same fields over a 3-year period did not result in a build-up of insect pests or a decline in grain yield.

Crop protection problems of smallholders farming maize in the Chokwe Irrigation Scheme in southern Mozambique were investigated in a long-term field study programme during 1984–1990. Downy mildew, Peronosclerospora sorghi (Weston & Uppal) C.G. Shaw, maize streak virus, stemborers (mainly Chilo partellus Swinhoe) and the multimammate rat (Praomys natalensis Smith) were the most important, with the first three showing highest incidence in the warm rainy season (October-March). Average percentage infestation of maize at 30 days after emergence in four successive rainy seasons were 11% for maize streak virus, 16% for downy mildew and 26% for stemborers. The multimammate rat was most abundant at the beginning of the cool, dry season (April-May). Maize streak virus attacks were aggravated when there was rainfall in the preceding cool, dry season. High rainfall in the early part of the warm season increased the likelihood of outbreaks of the multimammate rat in the subsequent cool season. Early sowing decreased the intensity of downy mildew and stemborers, but not of maize streak virus. In on-farm trials involving varieties with combined tolerance to maize streak virus and downy mildew, ESR-DMR-W from IITA (Nigeria) produced 32% more grain while CW-1, a locally bred improved variety, produced 31% more than the local unimproved variety.

Nightly catches of Scirpophaga nivella (F.) in light traps in rice plots in West Bengal, India, showed two discrete peaks of abundance in each trap-year corresponding to congenial weather and abundance of summer (mid-March-mid-June) and autumn (mid-July-mid-November) rice plants. Estimated generation times showed many overlapping generations in each trap a year. Variations in summer catches were significantly correlated (P < 0.01–0.05) with maximum temperature and minimum relative humidity of the day, and minimum temperature and wind speed of the night; whereas those in autumn catches were significantly associated with maximum temperature and minimum relative humidity of the night (P < 0.01–0.05). Autumn crops had more infestations, and sustained greater larval density than summer ones. Females were twice as heavy as males (2.1:1) and adults were heavier in October than in May. Catches of immature and mature females were consistently maximum at full moon and new moon, respectively.

Incidence of okra stemfly, Melanagromyza hibisci Spencer in India was high (40–60%) in winter months, i.e. during October, November, December and January sowings. Mean maximum and minimum temperature that prevailed 30 days after sowing had significant negative correlation with percentage main stem damage. Carbofuran, phorate, quinalphos and aldicarb, applied at 1 kg per ha reduced damage to main stem at the seedling stage but could not control subsequent damage to petioles. Eurytoma sp., a parasitoid on M. hibisci, had a high density-dependent relationship with its host, and played a significant role in keeping it under control.

Noctuid moths within and around the University of Ife campus were collected, using a mercury vapour light trap, from November 1976 to October 1977. In all, 338 individuals comprising 51 species were caught.

The moths were more abundant during the months of January, April, June and September while the lowest number was recorded in March. The calculated index of diversity tended to follow the same pattern as for abundance. The frequency distribution also shows that many more species were represented by two to five individuals than species represented by more than five individuals.

The possible underlying factors for these observations are discussed.