plant and insect interactions...insects in agriculture, many of which are mutualistic •insects...
TRANSCRIPT
-
Plant and Insect Interactions Within Agriculture
Drew Needham
-
Outline
• There is going to be a focus on plant-insect relationships in specifically agriculture
• Background
• Beneficial Ecosystem Services by Insects
• Detrimental Ecosystem Services by Insects
• Conclusion and Closing Remarks
• Time for Questions
-
Background Why is this important?
• Some perspective -There are over 900,000 species of insects known (80% of known species) -200 Million Insects/ human, 300 lbs of insects/ 1 lb of human
• 75% of crops rely on insect vectors for pollination, and insect pollination services are valued at $200 Billion worldwide each year (Natural Environment Research Council)
-
Beneficial Ecosystem Services
• Insects provide many beneficial services that directly and indirectly affect crops and other plants
• Many of the plant-insect relationships are mutualisms -Mutualism: Where both parties in the relationship benefit from the other
• Services provided: -Pollination -Nutrient cycling -Dung burial -Natural control of plant pests (Zhang et al., 2007)
-
Pollination
• The three main orders of insect pollinators are hymenoptera (bees and ants), lepidoptera (moths and butterflies), and diptera (true flies)
• Some species are generalist pollinators, and others can be very specific
• Usually a mutualistic relationship
-
Pollination
• One of the most common and famous pollinator is the honey bee (family Apoidae) -Generalist pollinator -Some plants must have honey bees (apples, sweet clover, squash, etc), while other plants are generalists (eggplant, soybean, pepper, etc) (UIUC)
-
Pollination
• The yucca-yucca moth relationship is an obligate mutualism for both parties -The yucca can only be pollinated by the yucca moth -The yucca moth oviposits exclusively in yucca plants, larvae feed on seeds (Pellmyr et al., 1996) -Coevolution
-
Nutrient Cycling
• Nutrient cycling -Many insects help to initially breakdown dead organic material -Flies and carrion beetles often feed on carcasses -Caddis larvae and caterpillars often feed on plant material -Helps to release stored nutrients back into the soil for future plant use
-
Dung Burial and Removal
• Animal waste has many stored nutrients needed for plant growth
• Dung beetles (Family scarabaeidea) remove waste and store it underground
• The stored dung not only provides nutrients to plants, but also improves the soil structure (Zhang et al., 2007)
• Added bonus for farms with both livestock and crops
-
Natural Pest Management
• There are a plethora of insects that are detrimental on plants, and fortunately, just as many insects that detrimental on the pests
• The Colorado Potato Beetle is the classic example of an agricultural pest controlled by beneficial insects, like Lebia grandis, a ground beetle of the family Carabidae (Hooks, 2013)
-
Detrimental Ecosystem Services
• Insects are responsible for BILLIONS of dollars of lost profits each year due to loss of yield and costs associated with pest management
• Insects can be detrimental in a variety of ways, but there are three main areas: -Herbivory -Competition for water -Disease transmission
-
Herbivory
• Herbivory is feeding on plants
• The most common means by which insects tend to be pests
• Have direct and indirect negative impact on yield
• The corn earworm, Helicoverpa zea, is caterpillar that alone incurs $2 Billion dollars in costs each year (Lopez et al., 1999)
-
Competition for Water
• Insects and plants both require water for survival
• The presence of insects, especially in large number, will decrease water availability
• Can be especially damaging in drought conditions, and costly if additional irrigation is required (Zhang et al., 2007)
-
Insects as Disease Vectors
• Many different Insects act as vectors for numerous plant diseases
• Whiteflies, hemipterans of the genus Bemisia, are notorious crop pests due to the many different plant diseases they transmit
• Whitefly-born diseases include, lettuce infectious yellows virus, asystasia golden mosaic virus, and African cassava mosaic virus (Brown et al., 1995)
-
Conclusion and Closing Remarks
• Insects play a major role in agriculture due to their close relationships with plants
• There are numerous beneficial services provided by insects in agriculture, many of which are mutualistic
• Insects also cause many problems for plants via a variety of mechanisms
• Many of these plant-insect relationships are very delicate and have coevolved over time
• Due to our dependence on agriculture as well as the services insects provide, humans need to be sure to maintain balance through proper management practices
-
Questions?
Thank you Ladybugs and Gentlemantids