Martin Kenne

• Maître de Conférence
• Ecologie Animale / Entomologie agricole / Biométrie et modélisation en écologie at University of Douala

The taxonomic status of the Pyrgomorphid genera Parapetasia Bolívar, 1884, and Loveridgacris Rehn, 1954 is complex and challenging. Here, we use a combination of morphological, distributional, and genetic data to revise the two genera and provide new information on their diversity. We describe a new species, Loveridgacris tectiferussp. nov., from T...

Synthetic pesticides present risks of pollution of the environment, humans and livestock and the alternative proposed today is to use botanical extracts in the fields against crop pests. But in North Cameroon, little information exists concerning the effect of these extracts on useful pollinating insects in general and no information exists in part...

A survey was undertaken from July 2021 to January 2022 in South-Cameroon on the biodiversity of micro-arthopods in the Memve'ele dam (Site 1), the tributary river (Site 2) and the adjacent river (Sites 3 and 4). Four abiotic parameters were measured in-situ while nine other abiotic parameters were measured in the laboratory using standard methods....

Synthetic pesticides present worldwide risks of contamination of humans, livestock and the environment due to the strong persistence and the toxic residues in fruits and vegetables. Natural biopesticides of local plant origin present low persistence and are the best alternative for the control of crop pests. In the Adamaoua region (Northern Cameroo...

A survey was undertaken from March to June 2014 on the biodiversity and the community structure of Chromista Cavalier-Smith, 1981 in Nyong and Kienke River mouths (South-Cameroon). In each river, raw waters were collected from upstream to downstream at four sites. Cells were counted using the Malassez cells procedure and species were identified. A...

Cowpea plants are damaged by insects in North-Cameroon. During ecological survey (2021 and 2022) in 44 plots of 4x3.5 m each, insects were captured on stems, leaves, flowers and pods, stored in vials containing 70° alcohol, identified in laboratory and the community structure was characterized. We captured 26,015 adults belonging to six orders, 13...

Among ants, Myrmicinae represents the most speciose subfamily. The venom composition previously described for these social insects is extremely variable, with alkaloids predominant in some genera while, conversely, proteomics studies have revealed that some myrmicine ant venoms are peptide-rich. Using integrated transcriptomic and proteomic approac...

Nesting system, diet behaviour, activity rhythm and predatory behaviour of Crematogaster (Nematocrema) stadelmanni Mayr, 1895 were studied in the field situation in suburbs of Douala (Littoral-Cameroon). Polycalic and polydomous nesting system were recorded. Large independent nests were positioned on the bark surface of trunks (50.8%) or the unders...

Urbanization is one of the most lasting anthropogenic disturbances threatening native species diversity including ants. Ants play important ecological functions such as seed dispersal, biological pest control, and bio-indicators of environmental changes. Herein, we investigated and tracked ant communities in three sites (rural, suburban and urban)...

Soil-dwelling ants are the most diverse and abundant groups of animals in most terrestrial ecosystems. However, reliable techniques for assessing the abundance and diversity of ant communities with respect to land management remain poorly studied. The present study aimed to evaluate the efficiency of three trapping procedures (Pitfall trapping, qua...

Soil-dwelling ants are the most diverse and abundant groups of animals in most terrestrial ecosystems. However, reliable techniques for assessing the abundance and diversity of ant communities with respect to land management remain poorly studied. The present study aimed to evaluate the efficiency of three trapping procedures (Pitfall trapping, qua...

The specimens studied were collected with sweep net and pitfall in the forests, agro-forests, herbaceous fallows, and crop fields of 14 localities in the southern part of Cameroon, from August 2015 to February 2018. The results show that Heteracrishannai sp. nov. and Heteracris lecoqi sp. nov. differ from previously known species of the same genus...

In the mutualisms involving certain pseudomyrmicine ants and different myrmecophytes (i.e., plants sheltering colonies of specialized “plant-ant” species in hollow structures), the ant venom contributes to the host plant biotic defenses by inducing the rapid paralysis of defoliating insects and causing intense pain to browsing mammals. Using integr...

Invasive species disrupt the organization and functioning of many ant communities. Little is known about ant assem- blages formerly in areas invaded by the little fire ant. In this study, we surveyed the same areas and compared the ant communities there when an invasive species first colonized the areas and 10 years later, using the same methodol...

The little fire ant, Wasmannia auropunctata Roger, is one of the world's most destructive invasive ants. It has been present in Cameroon for more than four decades, but its impact on local ant diversity is not known. We studied impact of W. auropunctata in three disturbed habitats located in rural and urban areas. We monitored ant diversity in both...

Field work on nest distribution of the pest ant Anoplolepis tenella in dominant vegetation type in Southern Cameroon

Melissotarsus ants have an extremely specialized set of behaviours. Both workers and gynes tunnel galleries in their host tree bark. Workers walk with their mesothoracic legs pointing upwards and tend Diaspididae hemiptera for their flesh. The ants use their forelegs to plug the galleries with silk that they secrete themselves. We hypothesised that...

Key evolutionary events associated with invasion success are traditionally thought to occur in the introduced, rather than the native range of species. In the invasive ant Wasmannia auropunctata, however, a shift in reproductive system has been demonstrated within the native range, from the sexual non‐dominant populations of natural habitats to the...

Details in lateral views of hairs present on the petiole. Magnification and scale bar are indicated for each scanning electron microscopic image. The terminal part of the hairs forms a point in P. megacephala var. 1 (A) and a brush in P. megacephala var. 2 (B). (TIF)

Minor of P. megacephala var. 1 (A) and P. megacephala var. 2 (B) in lateral views. Magnification and scale bar are indicated for each scanning electron microscopic image. (TIF)

Lateral views of the propodeum showing shorter spines in P. megacephala var 1. than in P. megacephala var. 2 (B). Magnification and scale bar are indicated for each scanning electron microscopic image. (TIF)

Background: Biological invasions are recognized as a major cause of biodiversity decline and have considerable impact on the economy and human health. The African big-headed ant Pheidole megacephala is considered one of the world's most harmful invasive species.

We investigated in the laboratory the initial behavior of propagules of the invasive ant Wasmannia auropunctata in Cameroon where it has been introduced. Both workers and queens at first feigned death (thanatosis), and then the workers slowly moved around the experimental arena; the queens did the same about 10 seconds later. Each queen antennated...

The little fire ant, Wasmannia auropunctata, is native to Central America, but has been introduced into many parts of the world. We examined the current distri-bution of W. auropunctata in Cameroon, tested for aggression between workers from different parts of the country, and examined the genotypes of workers, queens, and males to evaluate the mat...

The effect on plant growth of NaCl concentrations in soil, under semi-controlled conditions, water content and monovalent cations (Na+ and K+) distributions in seedlings of Avicennia germinans were studied. After 4 weeks of growth, results show that NaCl affected leaf growth more than roots and stems. For the two lower vegetal organs, 100 mmoles of...

Atopomyrmex mocquerysi ANDRÉ, 1889 is a West-Central African wood-excavating myrmicine species whose colonies construct galleries in the main live branches of their host trees, causing the distal parts of these branches to dry out. In southeastern Cameroon, this species was mainly found in woody savannahs that are burned annually. It was also prese...

We studied the behaviour of the invasive African myrmicine ant, Pheidole megacephala, when confronted with colonies of other common ant species in Cameroon, a part of its native range, and in Mexico, where it has been introduced. P. megacephala raided the nests of the other ants in both cases. Eleven species out of 12 put up a rather strong resista...

Anoplolepis tenella is a ground-nesting ant of the tropical forest zone of Central Africa, commonly associated with African root and tuber scale, Stictococcus vayssierei Richard, an emerging cassava pest. Understanding the ant's foraging activity and diet breadth is an important step towards developing control measures against S. vayssierei. The pr...

1. The ecological hypothesis predicts that multiple foundress colonies of social wasps may have a better survival rate and produce more brood per capita than single foundress colonies. With the aim of verifying if these characteristics exist in the primitively eusocial wasp species Belonogaster juncea juncea (L.), we monitored 49 foundations, inclu...

A study on the reproductive status of Belo-nogaster juncea juncea individuals was conducted in Cameroon on 21 pre-and 15 post-emergence colonies. We compared the females size and ovarian development, and verified if they were inseminated or not. Dominant females were inseminated, had well developed ovaries, and were the largest individuals in pre-e...

In Melissotarsus beccarii and M. weissi, two ant species which damage trees by digging nest galleries in bark, we observed numerous egg-producing physogastric queens situated more than one meter from each other, but within the same colony, making this the first record of oligogyny in this genus. Our analysis of ovarian development and degree of man...

The invasive African big-headed ant, Pheidole megacephala, is a dominant species in the many areas it has invaded. We examined whether one potential reason for its ecological success might be its predatory efficiency. We compared the density of termite nests in an area of Mexico invaded by P. megacephala with an adjacent area where P. megacephala i...

We studied the foraging and predatory behaviors of the invasive African myrmicine ant, Pheidole megacephala (F.) in its native range. Workers can singly capture a wide range of insects, including relatively large prey items. For still larger prey, they recruit at short range those nestmates situated within reach of an alarm pheromone and together s...

RESUME Les effets des engrais chimiques sur la valeur nutritionnelle des organes végétatifs ont été évalués afin d'identifier la fumure de redressement susceptible de permettre une amélioration de la composition chimique et de la production de matière sèche du manioc (Manihot esculenta) dans les zones rurales. 4 types d'engrais [engrais potassique...

a Département de biologie des organismes animaux, faculté des sciences de l'université de Douala, BP 24157, Douala, Cameroun b Laboratoire d'évolution et diversité biologique (UMR CNRS 5174), université Paul-Sabatier, 118, route de Narbonne, Abstract Workers of the pest ant Paratrechina longicornis participate in a type of group hunting. Each indiv...

concentrations of the serum parameters analyzed were similar for both sexes, whereas the atherogenic ration of cholesterol (ARC) was signifi cantly (p ! 0.036) higher in women. Serum lipids (total lipids, total cholesterol, low-density lipoprotein and phospholipids) correlated with vitamins A and E (p ! 0.05). Vitamins A and E were high-ly correlat...

Effects of 4 different concentrations of NaCl on plant height, on water content and on the distribution of monovalent cations (Na + and K + ) in organs of Avicennia germinans seedlings in semi-controlled conditions were investigated. After 4 weeks of cultivation, results showed that 200 mmoles sodium chloride reduced the height of leaves, but roots...

Les effets de la salinité sur la croissance des organes de cinq espèces légumineuses ont été évalués afin d\'identifier celles susceptibles d\'être cultivées sur des terres plus ou moins salées. 4 niveaux de salinité (0, 50, 100 et 200 mM de NaCl) ont été testés. Ainsi, l\'augmentation de la salinité entraîne chez Glycine max et Phaseolus vulgaris...

In this survey conducted in southern Cameroon, we compared ant-Hemiptera asso-ciations on plantations treated with insecticides, on plantations 2 years after insecticide treatments ceased, and on control lots that never received insecticide treatments. By eliminating arboreal-nesting ants, insecticides favored the presence of "ecologically dominant...

To strengthen the regeneration and management of Cameroon's coastal ecosystems, the biological characteristics of seedlings of Avicennia germinans (L.) Stearn and associated species were analysed from January 1999 to December 1999 in the mangroves under different environmental conditions. Site factors such as temperature, conductivity, salinity and...

We show in this study that Melissotarsus beccarii and M. weissi, two myrmicine species, are pest ants that dig galleries in the bark of trees in order to nest and attend Diaspididae (Hemiptera). Among the trees attacked figure species of economical importance such as Mangifera indica (mango tree; Anacardiaceae), Dacryodes edulis (safoo tree), and A...

We studied the predatory behavior of Myrmicaria opaciventris workers in three situations: (A) foraging workers from mature colonies under natural conditions; (B) young workers from parts of mature colonies in a situation of social regulation; and (C) young workers from incipient colonies. Termite workers, Microcerotermes fuscotibialis and Macroterm...

The colony ontogeny of Myrmicaria opaciventris was studied by comparing worker number and worker size in foundations with one queen (haplometrosis) or 2 to 6 queens (pleometrosis) and in established colonies. Measurements taken of head width related to scape length showed that the worker caste is weakly polymorphic and exhibits a unimodal size dist...

We studied the hunting behaviour of Myrmicaria opaciventris (Hymenoptera: Formicidae) in order to evaluate if it can be used as a biological control agent against the termites that damage sugarcane plantations. Hunting workers foraged in groups and recruited nestmates at short-range when they encountered large termite soldiers or groups of small te...

We recorded over the course of one year the location of nests of Myrmicaria opaciventris on five sites in the region surrounding Yaoundé (Cameroon). On these sites, the colonies are polydomous and polygynous. The size of the largest colony, which was made up of 27 nests, was evaluated at 216,575 ± 24,750 individuals of which 147,230 ± 15,336 were w...

The hunting behavior of Myrmicaria opaciventris was examined in order to evaluate if it can be used as a biological control agent against pest insects, particularly large individuals. To that end, we studied the predatory behavior of workers when confronted with katydids 10-20mm and 40-50mm long (two to seven times the length of the workers). Hunti...

In order to know the ecological impact of Myrmicaria opaciventris, a myrmicine ant known for its large polydomous colonies mostly installed in anthropized areas, we studied the diet and the rhythm of activity of this species. Workers gather numerous vegetal (sap, young twigs and buds, honeydew from attended Homopterans) and animal (whole prey, scav...

We examined nuptial flight in the ant Myrmicaria opaciventris. Swarming takes place after the first rains, or between March and April. Swarming occurs after a strong rain, between 8 a.m. and 11:30 a.m. Before flight, some females mate several times on the nest with several different males. After flight, the males form a swarm around an open site wh...

Myrmicaria opaciventris is a terrestrial myrmicine whose worker caste displays a monophasic polymorphism, which is an elementary stage of polymorphism. The study of the relationship between caste polymorphism and the division of labor within the external services shows differences when comparing proportions of minor, media, and major workers engage...