Team:Aix-Marseille/pontet
On the April 5th, 2018 we interview with Mr. André Pontet, an entomologist from the University of Lausanne.
For many people, studying insects is a rather "abstract" job. Can you tell us what are your main activities? What are the covered topics? What projects are you currently working on?
For many years now, I haven’t been doing entomology research, but I get involved in projects that describe the distribution of many insect species. I collect data for the distribution of Lepidoptera species in Switzerland with the CSCF (Centre Suisse de Cartographie de la Faune (FR), Swiss Wildlife Mapping Center (EN)) -To a lesser extent, Orthoptera and Coleoptera-. These projects combine observations made by scientists working on different themes, as well as direct observations made by amateurs, in a citizen participatory science approach. The data collection then makes it possible to compare the distribution of different species, as well as to see possible evolutions over time. The species’ monitoring leads to creating lists of threatened species. Thus, we can suggest protection system for areas where they are still present. Monitoring the evolution of the presence of invading species also benefits from these observations. Since my college studies, I have been interested in all the orders of insects, which allowed me to make didactic collections to present in a significant way the diversity of insects in Switzerland (Three groups gathering about 250 species). Furthermore, I take part of a study targeting the migration of the Vulcan (Vanessa Atlanta). It aims, in the pre-migratory period, to marking individuals captured in various places and then immediately released. During the migration period, by a Malay tent catch, at the Col de Bretolet in the Alps, a remarkable pathway of insects and birds in migration, we try to find individuals tagged a few weeks beforehand. In fact, my research covers various fields: from a studying the genetics of a group of small, tiny-shelled, ground-shelled snails to the neuro-physiology and endocrinology of fishes. Furthermore, I also the study small rodent brain (mouse, rat, Scots mouse) targeting the ontogenesis of locomotor behavior and ultrasonic vocalizations of the Scots mouse. Currently, I am also involved in ornithology, with a study of the temporal evolution of the birds of Lake Geneva, as well as the organization of the territory of the Woodcock in the Pre-Alps.
Where does this passion for entomology come from?
Since I was a child, I had a crazy passion for entomology. I was 6 years old when my mother raised some butterfly caterpillars until they hatched. This last event marked me! During the school holidays, she would take both my brother and myself to show us how to make insects collections, according to the indications given during a radio program, then to a recommended book, then to a butterfly specialist during a public exhibition of his collection. It's anecdotal, but it shows the importance of letting our children getting in touch with mother nature.
Which families are you most interested in?
The families that interest me the most are as previously said, the Lepidoptera. Among them, those of the family of the arctides, often called “Écailles” in French. Among these are species that not only perceive and avoid bat sonar, but are also capable of blurring. Other species of scales, diurnal, emit sounds by flying away when disturbed. These seem to surprise their predators and may allow them to flee. Others finally seem to indicate by their sounds that they are toxic. However, all the orders of insects present in Europe interest me, and it is the fact of finding similarities among all these species that allows me to understand certain biological phenomena.
Our team is currently working on bed bugs and particularly on Cimex Lectularius. What are the important things to know about this specie?
The Cimicidae are part of the order of the Heteroptera, formerly united with the Homoptera forming the obsolete order of the Hemiptera, with which they share their own characters, such as their stinging rostrum consisting of the mandible and the maxilla, but devoid of palps. The latter, however, has differences that separate the Heteroptera Homoptera. The Heteroptera have a rostrum of 4 articles, articulated, positioned in front of the head. It seems interesting to me to say that among the Heteroptera, we find species in all kinds of environments: it is a very rich and diversified order. For example, several species are aquatic, living in or the surface of the water. Some are predators, others parasitize plants but also animals, stinging and absorbing their fluids (blood, sap). It is the only order of Exopterygotes hemimetabolous insects (with progressive metamorphosis also called incomplete = paurometabol, 5 stages in general) which presents a wide range of ecological adaptations, comparable to that of Holometabolous endopterygotes (Coleoptera, Lepidoptera, Diptera and Hymenoptera to name only the most numerous). Bedbugs, Infraorder Cimicomorphs: for the details concerning this species, the specialists of this species are of course more adequate to answer you. I would just like to point out the particularity of their reproduction system: to deliver its sexual cells, the male directly pricks the abdomen of the female from the outside. The sexual cells are deposited in a pocket called spermatheca. However, as in other insects, fertilization occurs only during the laying. This detail about mating is interesting because the injury to the female may be the pathway for bacteria that later can infect people stung by these bugs. Transmission of staphylococci and enterococci has been suspected. The life expectancy of a bed bug can exceed one year, during which the female can lay up to 500 eggs, at a rate of one or two per day, which staggers births, thus improving her chances of settling effectively in places that are favorable to it. In addition, she can survive six months without feeding, which differs considerably from lice, for example, that dies quickly once they are away from their hosts. The temporary desertion of an apartment does not solve anything.
The current method for getting rid of bed bugs is eradication. What do you think of that?
Regarding the method or methods of eradication, it depends on what level we are: on a worldwide scale, we will never be able of eradicating bed bugs, it is impossible. We must learn how to live with them! Chemical control is inefficient in the medium or long term. Indeed, it is important to know that all species with large populations and high reproductive rate will undergo a selection of resistant strains to chemicals used against them. Chemical products are a bad approach for long-term eradication. On a building scale, we can probably overcome a bed bug infestation, but it can be difficult, depending on the state of the building (many cracks, insulation, paneling, heating pipes, ventilation...). Currently, there are several methods to control an infestation. The chemical and thermal methods are the most common, but do not exclude other complementary approaches (bed foot traps for example). The chemical method raises the problem of resistance. Chemical products can be toxic for the residents and their domestic animals. The thermal method is more difficult to apply and takes longer, but can, if it is well conducted, require only one intervention: it consists of heating the indoor air for several days at a high temperature (50 °C) lethal for bedbugs. In any case, all complementary approaches should be used simultaneously: the traps around the feet of beds, the systematic inspection of the objects introduced into an apartment can be effective, the very frequent use of the vacuum cleaner for mattresses and in places where bed bugs hide, as well as a high hygiene can reduce the risk of contamination. The use of repellents deposited or vaporized in the ambient air could contribute to the success of the prevention, if they are harmless for the residents. Other methods should be considered: it seems to me, for example, that a fight with traps to pheromones, to attract males or scramble could be promising because it is not toxic to humans.
Could there be any consequences for the ecosystem if bed bugs were to be eradicated?
As with all living species, without any exception, bed bugs take part of a complex food chain, in which the role of parasites of all kinds, but also viruses, exists. I do not know if this bug stings other species or if it is strictly subordinate to humans; if it is 100% specific to humans, the consequences of its disappearance would be imperceptible, because the factors affecting human demography are extremely numerous.