No abstract

The present study was carried out as a first documentation of short horn grasshoppers in the Menoua Division of Cameroon. A total of 1587 specimens were collected from six sites i.e. Dschang (265), Fokoue (253), Fongo -Tongo (267), Nkong -Ni (271), Penka Michel (268) and Santchou (263). Identification of these grasshoppers showed 28 species that included 22 Acrididae and 6 Pyrgomorphidae. The Acrididae belonged to 8 subfamilies (Acridinae, Catantopinae, Cyrtacanthacridinae, Eyprepocnemidinae, Oedipodinae, Oxyinae, Spathosterninae and Tropidopolinae) while the Pyrgomorphidae belonged to only one subfamily (Pyrgomorphinae). The Catantopinae (Acrididae) showed the highest number of species while Oxyinae, Spathosterninae and Tropidopolinae showed only one species each. Ten Acrididae species (Acanthacris ruficornis, Anacatantops sp, Catantops melanostictus, Coryphosima stenoptera, Cyrtacanthacris aeruginosa, Eyprepocnemis noxia, Gastrimargus africanus, Heteropternis sp, Ornithacris turbida, and Trilophidia conturbata ) and one Pyrgomorphidae (Zonocerus variegatus) were collected in all the six sites. Twelve Acrididae and 3 Pyrgomorphidae were collected during the wet and dry seasons. The importance of these grasshoppers in relation to pest activity, necrophagy, entomophagy, and entomotherapy, are discussed.

The standard karyotype of Oxycatantops spissus (Walker) (Orthoptera: Acrididae: Acridinae) from Limbe in the South West Province of Cameroon, comprises 2n = 23 acrocentric chromosomes in the male with the XO/XX sex determining mechanism [2n = 23 (22AA+XO)]. The karyotype structure is represented by five pairs of long (L1, L2, L3, L4, L5), three pairs of medium (M6, M7, M8) and three pairs of short (S9, S10, S11) autosomes. The acrocentric X chromosome is approximately equal in size to the short (S) autosomes. The meiotic process in this species was normal and chiasmate. Mean chiasma frequency in the wet season (16.36 ± 1.77) was significantly higher (p = 0.05) than in the dry season (15.00 ± 1.60). The differences probably lie in the fact that in the wet season many long bivalents had two or more chiasmata while in the dry season only a few long chromosomes had two or more chiasmata.

This article is a first record on the karyotypic features of Acrida turrita, Paracenema luculenta, and Morphacris fasciata (Orthoptera: Acrididae). The lacto-propionic orcein squash technique was used to prepare chromosome smears from the testes of specimens collected in May 2009 from the premises of the Institute for Rural Development (IRAD) Batoke, Limbe, in the South West Region of Cameroon. Analysis of these preparations revealed that the three species have the basic Acrididae complement consisting of 23 acrocentric chromosomes [2n♂= 23(22A+X0)]. The autosomes could be divided into 3 size groups: long, medium and short. The number of chromosomes in the different size groups varied among the species. A. turrita had 2 long, 7 medium and 2 short pairs of chromosomes while P. luculenta and M. fasciata each had 6 long, 2 medium and 3 short chromosome pairs. The mean chromosome lengths in the species were 71.80 ± 0.661µm, 83.70 ± 0.39µm, and 67.10 ± 0.31µm for A. turrita, P. luculenta and M. fasciata respectively. The X chromosome was medium in A. turrita and M. fasciata and long in P. luculenta. The chromosomes in these species were acro/telocentric in morphology.

Taphronota thaelephora Stal. 1873 is generating a lot of interest for biological and cytogenetic studies because it has demonstrated the potential for a future veritable pest in Cameroon. The lack of previously established karyotype for the species has necessitated this study. Testes from five adult individuals collected from Balepa -Mbouda in the West Region of Cameroon and treated with 1% colchicine were analyzed using the Lactic-Propionic Orcein squash technique. Mitotic metaphase chromosomes were measured directly from the microscope and pictures taken with the help of the Lietz photomicroscope. Pictures were processed with the Microsoft Office Picture Manager. The species revealed the standard Pyrgomorphidae karyotype of 2n♂= 19 acrocentric chromosomes. Mean length of the chromosomes ranged from 8.10±1.7 to 3.75±0.0 µm. Analysis of Relative Chromosome Lengths (RCL) revealed three distinct size groups of long, medium and short. The karyotype of T. thaelephora was made up of 2 pairs of long chromosomes (2LL) and the X-chromosome, 6 pairs of medium chromosomes (6MM) and 1 pair of short chromosomes (1SS). The mean lengths of the long, medium and short sized chromosomes were 7.2 µm, 4.8 µm and 3.51 µm respectively. The X-chromosome was the shortest of the large chromosomes with a mean length of 6.75 µm.