Forest ecosystems are of vital importance forliving organisms (Tüzün et al,2013) so they provide habitat for a vast array of plants and animals, many ofwhich are still undiscovered. Three hundred million people worldwide live inforests and 1.6 billion depend on them for hunting, gathering and medicine,forest products such as rubber and rattan, and small-scale agriculture so theirmanagement required considering all components of ecosystems.
One importantcomponent of forest ecosystems are insects which represent the most abundant groupin the phylum Arthropoda of the forest fauna. More than 900,000 species hadalready been described and are estimated to account for more than 80 % of allknown animal species (Baker 1972) and have been around for a long time, withfossil specimens of forest roundheaded borers having been found from 35 millionyears ago (Furniss and Carolin 1977). Insects perform many roles within forestsas pollinators, herbivores, carnivores, decomposers, and food sources for otherorganisms. Due to their dominant position in terms of population and theimportant roles they assume, they have considerable influence in the health ofa forest ecosystem.
They respond to the structural complexity of forests at different temporaland spatial scales and are markedly influenced by natural and anthropogenicdisturbances. Tropical forests are exposed to increasing levels of human-relateddisturbances, and in the near future, the last tracts of old-growth forests arelikely to be converted into human- modified landscapes (Wright, 2005; Melo et al., 2013a).
Habitat loss andfragmentation, logging, fire and hunting, combined with regional shifts inprecipitation, have caused an alarming loss of biodiversity, collapse of keyecosystem services and erosion of cultural heritage (Butchart et al., 2010; Laurance et al., 2012). Disturbance in an ecosystem like a forest may affectthe biodiversity of animals in different ways, according to their position in afood chain. Intheory at least, increased disturbance produces high species diversity in theprimary producers, intermediate diversity in herbivores and least diversity incarnivores (Huston, 1994). For example,forest fires have thepotential to effect significantly the insect diversity (ÖZKAZANÇ and ERTU?RUL,2011; Costello et al.,2011) by reducinginsect population densities directly, or by even contributing to an excessiveincrease in insect populations in reducing the populations of their naturalpredators. In both cases, the alteration of insect population densities poses athreat to the health of forest ecosystems.
Another case, logging residues livedin forests may serve as a substrate for the development of certain forest bark– and wood boring insects and in certain circumstances they can facilitate pestmultiplication and outbreaks (Schroeder, 2008) even though these loggingresidues are habitats of saproxylics beetles which play an important ecologicrole in forest ecosystem. It is clear that insect organism intervene inmodulation forest ecosystem and any variation in these ecosystems influence theirdiversity and composition of entomofauna and vice versa. The Republic of Benin located in West Africa is characterized by adiversity of agro-ecologic zone of which the vegetal area is progressivelydegrading and it is estimated that almost 70.000ha of forest are cleared eachyear (Djego et al., 2006). In its currentstate, Benin’s vegetation is characterized by its parceled nature and extremefragmentation due not only to climatic and edaphyc conditions, which varyrapidly according to the latitudinal gradient, but due mostly to strong anthropogenicpressure. Benin’s flora and vegetation, especially in its Southern part, arestrongly influenced by the enigmatic Dahomey Gap phenomenon. This is translatedby a flora poor in forest and endemic plant species; it is devoid of speciestypical to the dense evergreen rainforest.
Flora of the main plant formations is composed of Dense semi-deciduous forests, savannas,gallery forests and Swampy forests. Benin presents high population growth passing from 6769 914 inhabitant to2002 (RGPH3, 2002) to an estimate of 9. 983. 884 inhabitants (RGPH4, 2013) witha medium rate about 3.5 % of annual increase during last decade. Likewise several factorscontribute to the degradation of vegetation: anthropogenic factors(agriculture, exploitation of wood, crafts, medical use, vegetation fires) andnatural factors (the climate) (Sinsin & Kampmann, 2010).
The pressures on the forestsinclude to the loss of habitats due to extensive agriculture, the destructionof the natural environments linked to urbanization, the exploitation of woodand the abusive collection of medicinal plants. Given these diverse activities,man seems to be the first factor in the degradation of natural formations. Since, classifiedforests and national parks (called Protected Areas) have been established withthe goal to reduce these threats to the natural flora and the vegetationresources. Therefore, 58 Protected Areas have been created after a long processof which Lama Protected Forest which beneficed of an integral protection in itscentral core. But over forest ecosystems such as Lokoli Swampy Forest which isa community forest continues suffering from anthropogenic pressure on itsnatural resources like medicinal plants used. As insects arehighly susceptible to forest disturbance, it is important and interesting toevaluate the diversity of forest insect such as xylophagous and their naturalenemies in two kind of protected and unprotected forests.