Habitat Requirements of Insects Page 105

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Habitat Requirements of Insects (Page 105)
At the most basic level- The habitat must meet
all of the of the species needs or the species
cannot persist in that habitat.
Thus, the habitat must include all the needed
resources. However, it must also present them so
the insect can find them in space and time.
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Habitat Requirements of Insects (Page 105)
Some factors to consider Vagility- Habitat
suitability is influenced by a species
vagility, e. g. can it search 1 m2 or 1 hectare
Ability to survive unfavorable conditions- If a
habitat is unsuitable, e. g. lacks food, for part
of the year, then the species will require
diapause sites. Ability to locate resources
and/or mates- The habitat must provide the cues
necessary for food and mate location.
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Habitat Requirements of Insects (Page 105)
Habitat requirements include Food(s) for all
life stages- Host(s) or prey Alternate host(s)
or or prey Other foods, e. g. pollen and
nectar Refugia- Shelter form rain, predators,
etc. Diapause sites Cues for host/prey
exploitation- Cues involved in host/prey
finding Cues involved in synchronization with
host/prey Cues involved with mate location,
courtship and mating
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Habitat Requirements of Insects (Page 105)
Final considerations Species may be absent from
suitable habitats. They must colonize each
suitable habitat. More difficult for less vagile
species. More difficult as habitats become
fragmented. Smaller habitats are often less
stable. Local extinction is more likely,
requiring recolonization. These phenomena can
lead to metapopulations. The metapopulation
concept is relevant to agricultural systems
because crop fields are ephemeral habitats.
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Habitat Requirements of Insects (Page 105)
Metapopulations are populations divided into
partially independent geographic subunits, as
below
Time 1
Time 2
Habitat 1Population 1
Habitat 2Population 2
Habitat 1Population 1
Habitat 2Localextinction
Habitat 3Population 3
Habitat 4Local extinction
Habitat 3Population 3
Habitat 4Population 4Recolonized
Arrows indicate potential movement of individuals
between suitable habitats, dashed arrows indicate
movement is less likely, due to distance.