Rhyacionia buoliana (Schiff) (Lepidoptera: Tortricidae) was detected in 1985 in Chile and became ... more Rhyacionia buoliana (Schiff) (Lepidoptera: Tortricidae) was detected in 1985 in Chile and became one of important pest species in Chile. Population densities increase until in a few years to be more than 600 larvae per tree (including damages of over 10% of apical shoots). After some failed attempts to reduce an avoid the advance of the pest with chemical control, the government decided to implement classic biological control as the main method of control. We decided to introduce and release a solitary parasitoid known for his success in other countries: Orgilus obscurator (Ness) (Hym. Braconidae). Mayr. (Hymenoptera: Perilampidae) erupted with force not only in numbers but in behaviour too, because this particular species is known to be a hiperparasitoid. Then we begin to take into account the effect of other species such as the detected much earlier Temelucha platensis Brèthes (Hymenoptera: Ichneumonidae) in the behavior of O. obscurator (Lanfranco and Ramos 2010, Ramos and Lanfra...
The abundance of insect populations can change dramatically from generation to generation, and la... more The abundance of insect populations can change dramatically from generation to generation, and large increases are commonly known as "outbreaks". Insect outbreaks can be extremely destructive when the insect is considered as a crop or forest pest or it carries disease to humans, farm animals, or wildlife. Due to the economic losses caused by pests, it is very important to know and understand the processes (biotic or abiotic) that regulate insect populations. In Finland, pine sawflies (Hymenoptera, Diprionidae), consisting mainly in two species; Diprion pini (L.) and Neodiprion sertifer (Geoffroy) are one of the major defoliator groups of Scots pine forests. Several studies have recently estimated future outbreaks of pine sawflies, in the light of these future threats researchers considered that there is an increasing need in study their main controllers.
In this research, I studied one of the most important agents controlling pine sawflies populations, the cocoon predators, and how they are affected by the environment. Among other hypothesis and theoretical background, I took into account the Exploitation Ecosystem Hypothesis (EEH), which makes different predictions for predation depending on productivity levels. Hence, I focused my study on the different vegetation types of Scots pine forests. I used empirical models for the diprionid cocoon predation pressure, specifically generalized linear mixed model (GLMM) techniques. The mean percentage of predation was predicted as a function of forest vegetation type and season. The results of this research show that predation pressure is highly related with the type and structure of the forest where the pine sawflies predators live and predate. Rich forests (Mesic forests in this study) with higher vegetation diversity and structures supported the highest levels of pine sawflies cocoon predation.
Rhyacionia buoliana (Schiff) (Lepidoptera: Tortricidae) was detected in 1985 in Chile and became ... more Rhyacionia buoliana (Schiff) (Lepidoptera: Tortricidae) was detected in 1985 in Chile and became one of important pest species in Chile. Population densities increase until in a few years to be more than 600 larvae per tree (including damages of over 10% of apical shoots). After some failed attempts to reduce an avoid the advance of the pest with chemical control, the government decided to implement classic biological control as the main method of control. We decided to introduce and release a solitary parasitoid known for his success in other countries: Orgilus obscurator (Ness) (Hym. Braconidae). Mayr. (Hymenoptera: Perilampidae) erupted with force not only in numbers but in behaviour too, because this particular species is known to be a hiperparasitoid. Then we begin to take into account the effect of other species such as the detected much earlier Temelucha platensis Brèthes (Hymenoptera: Ichneumonidae) in the behavior of O. obscurator (Lanfranco and Ramos 2010, Ramos and Lanfra...
The abundance of insect populations can change dramatically from generation to generation, and la... more The abundance of insect populations can change dramatically from generation to generation, and large increases are commonly known as "outbreaks". Insect outbreaks can be extremely destructive when the insect is considered as a crop or forest pest or it carries disease to humans, farm animals, or wildlife. Due to the economic losses caused by pests, it is very important to know and understand the processes (biotic or abiotic) that regulate insect populations. In Finland, pine sawflies (Hymenoptera, Diprionidae), consisting mainly in two species; Diprion pini (L.) and Neodiprion sertifer (Geoffroy) are one of the major defoliator groups of Scots pine forests. Several studies have recently estimated future outbreaks of pine sawflies, in the light of these future threats researchers considered that there is an increasing need in study their main controllers.
In this research, I studied one of the most important agents controlling pine sawflies populations, the cocoon predators, and how they are affected by the environment. Among other hypothesis and theoretical background, I took into account the Exploitation Ecosystem Hypothesis (EEH), which makes different predictions for predation depending on productivity levels. Hence, I focused my study on the different vegetation types of Scots pine forests. I used empirical models for the diprionid cocoon predation pressure, specifically generalized linear mixed model (GLMM) techniques. The mean percentage of predation was predicted as a function of forest vegetation type and season. The results of this research show that predation pressure is highly related with the type and structure of the forest where the pine sawflies predators live and predate. Rich forests (Mesic forests in this study) with higher vegetation diversity and structures supported the highest levels of pine sawflies cocoon predation.
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In this research, I studied one of the most important agents controlling pine sawflies populations, the cocoon predators, and how they are affected by the environment. Among other hypothesis and theoretical background, I took into account the Exploitation Ecosystem Hypothesis (EEH), which makes different predictions for predation depending on productivity levels. Hence, I focused my study on the different vegetation types of Scots pine forests. I used empirical models for the diprionid cocoon predation pressure, specifically generalized linear mixed model (GLMM) techniques. The mean percentage of predation was predicted as a function of forest vegetation type and season. The results of this research show that predation pressure is highly related with the type and structure of the forest where the pine sawflies predators live and predate. Rich forests (Mesic forests in this study) with higher vegetation diversity and structures supported the highest levels of pine sawflies cocoon predation.
In this research, I studied one of the most important agents controlling pine sawflies populations, the cocoon predators, and how they are affected by the environment. Among other hypothesis and theoretical background, I took into account the Exploitation Ecosystem Hypothesis (EEH), which makes different predictions for predation depending on productivity levels. Hence, I focused my study on the different vegetation types of Scots pine forests. I used empirical models for the diprionid cocoon predation pressure, specifically generalized linear mixed model (GLMM) techniques. The mean percentage of predation was predicted as a function of forest vegetation type and season. The results of this research show that predation pressure is highly related with the type and structure of the forest where the pine sawflies predators live and predate. Rich forests (Mesic forests in this study) with higher vegetation diversity and structures supported the highest levels of pine sawflies cocoon predation.