Climate warming is considered to be among the most serious of anthropogenic stresses to the envir... more Climate warming is considered to be among the most serious of anthropogenic stresses to the environment, because it not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human‐mediated threats. The associated consequences are potentially severe, particularly in terms of threats to species preservation, as well as in the preservation of an array of ecosystem services provided by biodiversity. Among the most affected groups of animals are insects—central components of many ecosystems—for which climate change has pervasive effects from individuals to communities. In this contribution to the scientists' warning series, we summarize the effect of the gradual global surface temperature increase on insects, in terms of physiology, behavior, phenology, distribution, and species interactions, as well as the effect of increased frequency and duration of extreme events such as hot and cold spells, fires, droughts, and floods on these parameters. ...
The MODIRISK project studied mosquito biodiversity and monitored and predicted biodiversity chang... more The MODIRISK project studied mosquito biodiversity and monitored and predicted biodiversity changes, to actively prepare to address issues of biodiversity change, especially invasive species and new pathogen risks. This work is essential given continuing global changes that may create suitable conditions for invasive species spread and the (re-)emergence of vector-borne diseases in Europe. Key strengths of MODIRISK, in the context of sustainable development, were the links between biodiversity and health and the environment, and its contribution to the development of tools for describing the spatial distribution of mosquito biodiversity. MODIRISK addressed key topics of the global Diversitas initiative, which was a main driver of the Belspo ‘Science for a Sustainable Development’ research program. Three different MODIRISK datasets were published in the Global Biodiversity Information Facility (GBIF): the Collection dataset (the Culicidae collection of the Museum of Natural History i...
Natural plant extracts are considered as promising tools to fight pests such as phytophagous mite... more Natural plant extracts are considered as promising tools to fight pests such as phytophagous mites and particularly against Tetranychus urticae that causes damage of economic importance in agriculture. The aim of the present work was to analyze the persistence of their biocidal activity and to investigate the possibility of extending their activities against T. urticae. Three essential oils from Deverra scoparia, Hertia cheirifolia and Santolina africana, and one distillate from Allium sativum are effective in controlling the two spotted spider mite T. urticae. The persistence of the plant extracts was evaluated and compared with and without a non-ionic surfactant composed of monosorbitanoleate (Tween®20). Without Tween®20 and five days following treatment, the four extracts rapidly lost their toxicity against T. urticae indicating low persistence of their biological activity. With Tween®20, their persistence significantly increased and lasted 10 days. The combination with Tween®20 ...
Communications in agricultural and applied biological sciences, 2010
Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more... more Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more particularly in the Sahelian zone. Present control methods are only partially efficient. In a previous study, we tested the potentiality of a sterile insect technique (SIT). Males of S. gregaria appeared to be much radiosensitive as already a dose of 3 Gy limited their survival. Gamma-radiations are known to damages the epithelial tissue of midgut, which affects the alimentation in insects. In this work, we show how digestive system of S. gregaria males is affected when submitted to a dose of 4 gamma rays. Nutrition is affected as males stop feeding soon after irradiation and progressively lose weight. Histological analyses on the midgut showed important epithelium damages. The regenerative cells by which the epithelial cells are replaced were damaged on the first days following irradiation. Consequently, regenerative cells are unable to divide and replace the normal loss of midgut cell...
Communications in agricultural and applied biological sciences, 2005
Essential oils from seven plants species currently found in Cameroon were extracted by steam dist... more Essential oils from seven plants species currently found in Cameroon were extracted by steam distillation and tested for their insecticidal activities against Sitophilus zeamats Motsch. Responses varied with the test applied and the plant species. For the contact toxicity, the acetone was used in order to dilute the pure essential oil. Formulations of 1% of essential oils of Xylopia aethiopica and Ocimum gratissimum were the most toxic and led to 96 and 98% of mortality respectively after 24 h. There was no death in control (0% of mortality). Fumigation test were done by applying 300 microl of pure essential oils in the bottom of closed 800 ml glass containers. In that case, the essential oil of Hyptis spicigera was the most toxic (fumigant) after 48 hours of fumigation followed by Annona seregalensis and Xylopia aethiopica 96 and 95% of mortality respectively. Some of the essential oils of plant species tested are promising for pest control in farmer granaries. However, further inv...
Climate warming is considered to be among the most serious of anthropogenic stresses to the envir... more Climate warming is considered to be among the most serious of anthropogenic stresses to the environment, because it not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human‐mediated threats. The associated consequences are potentially severe, particularly in terms of threats to species preservation, as well as in the preservation of an array of ecosystem services provided by biodiversity. Among the most affected groups of animals are insects—central components of many ecosystems—for which climate change has pervasive effects from individuals to communities. In this contribution to the scientists' warning series, we summarize the effect of the gradual global surface temperature increase on insects, in terms of physiology, behavior, phenology, distribution, and species interactions, as well as the effect of increased frequency and duration of extreme events such as hot and cold spells, fires, droughts, and floods on these parameters. ...
The MODIRISK project studied mosquito biodiversity and monitored and predicted biodiversity chang... more The MODIRISK project studied mosquito biodiversity and monitored and predicted biodiversity changes, to actively prepare to address issues of biodiversity change, especially invasive species and new pathogen risks. This work is essential given continuing global changes that may create suitable conditions for invasive species spread and the (re-)emergence of vector-borne diseases in Europe. Key strengths of MODIRISK, in the context of sustainable development, were the links between biodiversity and health and the environment, and its contribution to the development of tools for describing the spatial distribution of mosquito biodiversity. MODIRISK addressed key topics of the global Diversitas initiative, which was a main driver of the Belspo ‘Science for a Sustainable Development’ research program. Three different MODIRISK datasets were published in the Global Biodiversity Information Facility (GBIF): the Collection dataset (the Culicidae collection of the Museum of Natural History i...
Natural plant extracts are considered as promising tools to fight pests such as phytophagous mite... more Natural plant extracts are considered as promising tools to fight pests such as phytophagous mites and particularly against Tetranychus urticae that causes damage of economic importance in agriculture. The aim of the present work was to analyze the persistence of their biocidal activity and to investigate the possibility of extending their activities against T. urticae. Three essential oils from Deverra scoparia, Hertia cheirifolia and Santolina africana, and one distillate from Allium sativum are effective in controlling the two spotted spider mite T. urticae. The persistence of the plant extracts was evaluated and compared with and without a non-ionic surfactant composed of monosorbitanoleate (Tween®20). Without Tween®20 and five days following treatment, the four extracts rapidly lost their toxicity against T. urticae indicating low persistence of their biological activity. With Tween®20, their persistence significantly increased and lasted 10 days. The combination with Tween®20 ...
Communications in agricultural and applied biological sciences, 2010
Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more... more Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more particularly in the Sahelian zone. Present control methods are only partially efficient. In a previous study, we tested the potentiality of a sterile insect technique (SIT). Males of S. gregaria appeared to be much radiosensitive as already a dose of 3 Gy limited their survival. Gamma-radiations are known to damages the epithelial tissue of midgut, which affects the alimentation in insects. In this work, we show how digestive system of S. gregaria males is affected when submitted to a dose of 4 gamma rays. Nutrition is affected as males stop feeding soon after irradiation and progressively lose weight. Histological analyses on the midgut showed important epithelium damages. The regenerative cells by which the epithelial cells are replaced were damaged on the first days following irradiation. Consequently, regenerative cells are unable to divide and replace the normal loss of midgut cell...
Communications in agricultural and applied biological sciences, 2005
Essential oils from seven plants species currently found in Cameroon were extracted by steam dist... more Essential oils from seven plants species currently found in Cameroon were extracted by steam distillation and tested for their insecticidal activities against Sitophilus zeamats Motsch. Responses varied with the test applied and the plant species. For the contact toxicity, the acetone was used in order to dilute the pure essential oil. Formulations of 1% of essential oils of Xylopia aethiopica and Ocimum gratissimum were the most toxic and led to 96 and 98% of mortality respectively after 24 h. There was no death in control (0% of mortality). Fumigation test were done by applying 300 microl of pure essential oils in the bottom of closed 800 ml glass containers. In that case, the essential oil of Hyptis spicigera was the most toxic (fumigant) after 48 hours of fumigation followed by Annona seregalensis and Xylopia aethiopica 96 and 95% of mortality respectively. Some of the essential oils of plant species tested are promising for pest control in farmer granaries. However, further inv...
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