Life‐history traits of the edible stinkbug, Encosternum delegorguei (Hem., Tessaratomidae), a traditional food in southern Africa

Abstract

Little is known of the life history of the edible stinkbug, Encosternum delegorguei, although it is an important food for people living in north‐eastern South Africa and southern Zimbabwe. The present study aimed to establish key elements influencing long‐term sustainable harvesting. Outdoor insectaries of two sizes were constructed to observe: daily activity, utilization of plants, copulation, oviposition, eclosion and survival from May 2006 to February 2007. The rest of the annual life cycle was observed in the field in March and April 2007 and identified as univoltine. In autumn (May) E. delegorguei entered reproductive diapause and aggregated within the escarpment mist‐belt where it survived the winter on vapour condensation without feeding. Monthly dissections showed that abdominal fat content was highest in June. In spring (September) E. delegorguei fed on sap of the trees Combretum imberbe, Combretum molle, Peltophorum africanum, to a lesser degree on Dodonaea viscosa and the grass Pennisetum clandestinum. Copulation occurred in October and November. An overall total of 1752 E. delegorguei eggs were laid by 103 females and incubation time averaged 18.7 ± 9.0 days (range 7–37) at outdoor temperature ranging from 11°C to 25°C. The mean number of eggs in 64 egg masses was 27.4 ± 13.9 (range of 2–56 eggs). Shade cloth (68.8%) was the most commonly used substrate for depositing eggs followed by P. clandestinum (12.5%), C. imberbe (7.8%), P. africanum (6.3%), D. viscosa (1.6%), C. molle (1.6%) and C. erythrophyllum (1.6%). The parasitoid wasp, Anastatus sp. (Hymenoptera: Eupelmidae) infected 57% of the eggs deposited by captive females. Availability of food plants in combination with parasitoid threat may be a reason for seasonal migration between overwintering sites within the mist‐belt and summer oviposition sites. Diminishing harvests could be attributed to fuelwood harvesting of food plants in the summer sites.

Less Diverse Pentatomoid Families (Acanthosomatidae, Canopidae, Dinidoridae, Megarididae, Phloeidae, and Tessaratomidae)

“…All species are univoltine and usually use more than one host plant throughout its life cycle (Schaefer et al 2000 ;Dzerefos et al 2009 ), with biological aspects very similar to Dinidoridae (see item 3.3). Depending on the species, females can lay in masses of four rows (3-4-4-3 formula), with an average of 14-28 eggs per clutch.…”

“…Only a few species of tessaratomids have their biology studied (McDonald 1969 ;Malipatil and Kumar 1975 ;Schaefer et al 2000 ;Dzerefos et al 2009 ); most of the available data is limited to label data or other types of fi eld observation. Schaefer and Ahmad ( 1987 ) refer to known host plants, and Schaefer et al ( 2000 ) reviewed and discussed the available data of the species related to crops.…”

“…Fertility is considered low, not exceeding 1-2 clutches/female (Schaefer et al 2000 ). Eggs of Encosternum delegorguei Spinola took an average of 18 ± 9 days to hatch (temperatures ranging from 11 to 25 °C), while the nymphs took four months to reach adulthood (Dzerefos et al 2009 ). Adults of this species overwinter from autumn to late winter.…”

Fecundity and Survival of the Edible Insect,Hemijana variegataRothschild 1917 (Lepidoptera:Eupterotidae) under Ambient Laboratory Conditions

“…However, before such tools can be developed it is necessary to understand the biology of the species (Dzerefos et al 2009). Recently, there have been initiatives to rear a number of edible insects for commercial purposes and such projects rely on accurate information on the biology of the species in question (Ghaly 2009).…”

Comparative ethnoentomology of edible stinkbugs in southern Africa and sustainable management considerations

“…This is very convenient for harvesters because at this time of year home grown produce and wild edible plants are scarce [10,23]. The apparently increasing availability of stinkbugs for sale in South Africa has led to a concern that harvesting could be unsustainable [24], and it is therefore crucial to have reliable information on their usage.…”