Biology, predatory activity and peoples’perceptions towards apefly (spalgis spp.) in Tanzania

Abstract

In June 2017, farmers in central and northern Tanzania reported the occurrence of what they called an unusual insect with a human-like facial appearance that they referred to as “Kidudu-mtu.” The reports prompted the need to assess the identity and occurrence of the insect in Tanzania. This research was conducted between March and August 2018 in Iringa, Morogoro, Shinyanga, Geita and Arusha regions. A total of 89 people in the study regions were purposely interviewed to determine their knowledge, perceptions and reactions towards the insect. Insect samples were collected and submitted to the Tropical Pesticide Research Institute (TPRI) for preliminary identification and toxicity test. Molecular identification was done at the Nelson Mandela African Institution of Science and Technology (NM-AIST) laboratory. The insect’s predatory activity against the papaya mealybug (Paracoccus marginatus Williams and Granara de Willink) was assessed at Tanzania Agricultural Research Institute (TARI) Tengeru. The insect was preliminarily identified as a member of the genus Spalgis present in three regions on papaya and cassava plants. The majority (92.1%) of the respondents perceived the insect as poisonous. In the toxicity tests, no death or toxic signs were displayed by the mice and no significant differences (P>0.05) were observed between the control and treated mice during hematological, biochemical and histopathological examination results except increase in liver weight which was considered non-adverse based on available protocol. The molecular analysis revealed 99% similarity with Spalgis lemolea lemolea (Druce) commonly known as Apefly. Under laboratory conditions, the insect completed its life cycle within 23 days with 4 larval instars. The female laid an average of 68 eggs in groups of 2 to 7 at different sites after 4-5 days of emergence. The predatory activity studies showed the consumption of mealybugs by the Apefly increased as the insect developed. The average number of mealybug eggs, nymphs and adults consumed by a single Apefly larva was 1983 ± 117, 123 ± 6 and 80 ± 9 individuals, respectively. Further studies to asses biological processes associated with an increase in liver weight on mice and determine predatory potential of Apefly under field conditions are recommended.