Pitfall traps were used to monitor the activity of ants in a forest floor and a one-year-old fallow plot in Ile-Ife, Nigeria, at monthly intervals between November 1980 and October 1981. Similar studies were carried out between October 1987 and June 1988. These studies also included manual collection of ants from the floor of the experimental plots. Of all the 10 species of ants recorded, Pbeihk rrassinoda was the most abundant in the forest and fallow plots both in 1980-81 and 1987-88. R rrassinoda accounted for 52 percent and 88 percent of the ant populations collected manually from the forest and fallow plots respectively between December 1987 and June 1988. This species was also significantly higher in the pitfall catches of the fallow than the forest plots. Pitfall traps were not effective in sampling the populations of the belligerent Doryfus nigricans. The data are consistent with the widely accepted notion that forested areas support less ants than unforested areas. Differences in physical habitat characteristics, food availability, nesting habits, predation and microenvironmental factors were considered responsible for the differences in activities and abundance of ants in the forest and fallow plots.

Background Forensic entomology is evolving into entomotoxicology, which is a critical approach in forensic toxicology that alternatively assesses presence of toxins in insects that have eaten a decomposing cadaver. Toxic substances in or on a dead body may accumulate in the tissues of fly maggots while feeding on the body and thus may alter their developmental rate. Thus, four out of eight healthy pigs (Sus scrofa Linn.) that weighed on the average 22.3 ± 1.9 kg were sacrificed with zinc phosphide as food poison, while the remaining four pigs were sacrificed by strangulation during the rainy and dry seasons of 2014 and 2015 respectively. Their bodies were deposited in a building to mimic indoor decomposition. The building is on 6° 15′ 18.06″ N and 7° 06′ 41.37″ E at Nnamdi Azikiwe University Awka, Anambra State, Nigeria. The effect of the zinc phosphide on the decomposition duration of the cadavers was monitored. Toxicological assessment of zinc and phosphorus on maggots found on the cadavers was performed with an atomic absorption spectrophotometer. Findings The zinc phosphide did not affect the decomposition duration of the cadaver and did not prolong or shortened the life cycle of the fly maggots when compared with the control (strangled pig cadaver). For the poisoned cadavers, the atomic absorption spectrophotometer detected zinc in the maggot tissues collected from them while phosphorus was not detected. Neither zinc nor phosphorus was detected in the maggot tissues collected from the strangled cadavers. Conclusions The study showed that the zinc component in the zinc phosphide commonly used as rodenticide in Awka can be detected in maggots collected from such a suspected poisoned cadaver. Other implications related to toxicological studies on cadaveric insects in forensic entomology and serving as alternative matrices in forensic toxicology in any questionable death were also highlighted.

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A study was carried out to access the insect fauna of a fallow plot in Awka, Nigeria, in relation to their diel activities and to report any differences in the pitfall catches as a result of differences in the fluid used. The fluid used in the three sets of six traps installed bimonthly at the sites for 12 hours in each case were 5% formalin, water with 0.01% banana flavour essence and ordinary water. Using Student t-test, statistical differences existed in the diurnal and nocturnal activities of the Sminthurididae, Poduromorpha, Diptera, Acantholepsis, Paratrechina sp. and Camponotus, at probability level P<0 05 with more nocturnal catches obtained in all cases for water with banana flavour essence. Similarly statistical differences also existed in the trapp ng o Poduromorpha, Entomobryomorpha, Acantholepsis and Camponotus sp., for pitfall traps containing water. For pitfall traps with 5% formalin statistical differences, existed in the trapping Sminthurididae Poduromorpha, Diptera, Acheta lefevrei, Acantholepsis sp., Hymenoptera (other than formicids) and orthopteran larvae, with more nocturnal catches recorded for the pitfall traps with banana flavour essence, possibly indicating the attractive properties o this particular avour essence. The Analysis of Variance (ANOVA) test also showed that statistical differences existed in the diurnal and nocturnal catches of insects obtained using the three killing agents. The Fisher's Probability Least Signi cance Difference (F-LSD) also established statistical differences in the catches made using banana flavour essence and water and also with ord nary water and formalin, with the nocturnal catches being higher than the diurnal catches. The F-LSD also confirmed that the total nocturnal catches were s gnificantly higher than the total diurnal catches obtained using all the three killing agents. An approximate ratio o 1 2 was also obtained in the catches in relation to diurnal and nocturnal activities respectively.

The pitfall trap was used in the study of the dipteran populations of an abattoir and a contiguous fallow plot, in relation to their relative abundance and distribution. A total number of 140 adult species of Synydas and Stomorhina cribrata, and 400 dipteran larvae were captured at the abattoir using pit all techniques, with correspondingly fewer species of similar dipterans trapped at the contiguous fallow plot. Significant difference existed in the trapping of the Diptera larvae with more trapped at the abattoir than the fallow plot using Student t-test. There was also a preponderance of calliphorid species at the abattoir when the sweep net was used, with these species implicated as being potential pests of med cal and forensic importance. The presence of Sarcophaga sp. and Fannia canicularis in the sweep net collection at the abattoir was also traced to the presence of decaying fall-offs from carcass. Other possible implications of the collected dipteran species at the abattoir and its vicinity were also discussed f i .