Foliage/Sap/Root feeding Coleoptera
Leaf Beetle (Chrysomelidae)
Zygogramma
exclamationis
Also known as the sunflower beetle, these insects feed
exclusively on sunflowers. Adults, which range in size from 6-13mm in length,
feed, mate, and lay eggs in late May or early June. Adults feed on stems and
the undersides of leaves. It is possible to distinguish this damage from that
of the larvae, which chew holes in leaves and may completely defoliate a plant
during their development if they are numerous. Larvae can occasionally be found
feeding among florets.
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Zygogramma exclamationis |
Larvae
feeding on leaves
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Euphoria inda L. (Scarabaeidae, Cetoniinae) The bumble flower beetle is an
interesting scarab that mimics bumblebees in flight and is myrmecophilous
(develops in ant nests). Although generalists as adults, these beetles were exceptionally
common on wild sunflower during the 2000 field season. They were observed
feeding en masse on sap at holes that they gouge from sunflower stalks.
Interestingly, these holes then attract a multitude of other insects including
butterflies, wasps, longhorn beetles, and flies (during the day) and a variety
of moths (at night) that are attracted to the sweet sap.
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Four E. inda gouging a
sunflower stalk
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Euphoria inda
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Moths feeding at the sap flow
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Phyllophaga lanceolata
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Ligyrus gibbosus |
Phyllophaga lanceolata (Melolonthinae)
These june beetles are encountered commonly at our field site, and during the
summer of 2000, male and female beetles were observed feeding on small
drought-stressed H. annuus.
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Ligyrus
gibbosus (Dynastinae) The "carrot beetle" is commonly
found feeding on the roots of wild sunflower when plants are uprooted.
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Longhorns
(Cerambycidae) Five species of longhorn beetles have been collected on
sunflower at our site. Of these, Dectes texanus is
sometimes a stem-feeding pest of cultivated sunflower. Ataxia and Mecas spp. are
also associated with plant stems. Batyle
suturalis is a common pollinator, while Megacyllene decora has been
collected at the sap flows created by Euphoria inda (Scarabaeidae, see
above).
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Ataxia hubbardi
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Batyle suturalis
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Dectes texanus
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Mecas pergrata |
Megacyllene decora |
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