Morphology, development, and reproduction of Eyprepocnemis plorans ibandana (Orthoptera: Acrididae) in South Cameroon rainforests

Abstract

Eyprepocnemis plorans ibandana is a very common grasshopper species in open environments and agricultural systems of tropical Africa. It is a pest that significantly benefits from forest degradation in southern Cameroon, hence the need to study the bioecology of this subspecies. We studied the reproduction as well as the morphological characteristics and development times of the post-embryonic instars of E. p. ibandana. Sixty-one adult pairs were obtained from sixth instar nymphs caught in grassy vegetation in the Nkolbisson area (Yaoundé) and bred in the laboratory. After hatching, the first instar nymphs were individually placed in cages and fed every two days using fresh leaves of Manihot esculenta. The postembryonic development of E. p. ibandana took six instars in the male and six to seven instars in the female. Mean nymphal development took 79.16 ± 0.51 days in males, 89.93 ± 0.58 days in 6 instar females and 94.96 ± 1.22 days in 7 instar females. The survival rate of the first instar was low (53%). However, from the second instar on the survival rate was very high (> 87%). Sexual dimorphism is distinct in adults, fifth and sixth nymphal instars. Adults of E. p. ibandana took on average 32.57 ± 3.88 days to start mating, and mating lasted 2.12 h on average (1–3 h). Oviposition took place on average 52.03 ± 5 days after first mating; each female deposited one to eleven oothecae with an average of 34.93 ± 2.37 eggs per ootheca. Our study provides important information for the control of this subspecies in southern Cameroon.

Morphology, development and reproduction of <em>Atractomorpha acutipennis</em> (Guérin-Méneville, 1844) (Orthoptera: Pyrgomorphidae)

“…This result might be linked to the high number of the post-embryonic stages of the females. The same result was obtained by Sai-Keung (1973) in A. sinensis in Iceland andNkwala et al (2019) in Eyprepocnemis plorans ibandana in Southern Cameroon. Taphronota ferruginae (Kekeunou et al 2018) and Pyrgomorpha vignaudii (Kekeunou et al 2015) showed a non significant difference between male and female total developmental time.…”

“…The variation in number of instars according to sex were also noted in several species of Acrididae such as Atractomorpha sinensis Bolívar, 1905in Iceland (Sai-Keung 1973 Cameroon, E. p. meridionalis Uvarov, 1921(Hernán dez and Presa 1984) in Spain, and E. p. plorans (Charpentier, 1825 (Schmidt et al 1996) in Sardinia. However, as in this study Sai-Keung (1973) has observed a constant number of instar in each sex (7 in male and 8 in female of A. sinensis) whereas there is a variation in female of E. plorans ibandana: 6 or 7 in female and 6 in male (Nkwala et al 2019).…”

“…This grasshopper is found throughout the southern part of the African continent. It has been reported on the West African coast bordering the Indian Ocean, in Madagascar around the Nossi-Bé region (Ottes 1994) and in several West African countries, East, South (Paraïso et al 2012) and Center including Benin, Guinea-Bissau, Mali, Liberia, Niger, Nigeria, Cameroon, Senegal, Sierra Leone, Chad and Togo (Mestre and Chiffaud 2006). In nature, there are three known subspecies: A. acutipennis acutipennis (Guérin-Méneville, 1844) in Madagascar; A. acutipennis brevis (Uvarov, 1938) in South-West Asia and in the North-East African region; A. acutipennis gerstaeckeri (Bolívar, 1884) in sub-saharan Africa (Banerjee and Kevan 1960) and Madagascar (Roy 2003).…”

Grasshopper (Orthoptera: Acridomorpha) diversity in response to fallow-land use in southern Cameroon with recommendations for land management

“…Of the species found in the forests in the same region in southern Cameroon ( Oumarou-Ngoute et al 2020 ), one ( Serpusia opacula ) was ‘less abundant’ in the fallow-land, while the rest were rare or absent, including Mazaea granulosa , the most common species in the forests that was not found in the fallow-land at all. The species that increase ( Z. variegatus , E. plorans , and C. sylvestris ), which are known as crop pests ( Okunlola and Ofuya 2010 , Oladele et al 2014 ), find suitable environments for their development ( Nkwala et al 2019 ).…”