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Aposematism Phenotypes Reflex Bleeding: Hippodamia Convergens

The atlas Ladybirds (Coccinellidae) of Britain and Ireland published in 2011[27] showed a decline of more than 20% in native species due to environmental changes and competition from foreign invaders. The distribution maps, compiled over a 20-year period with help from thousands of volunteers, showed a decline in the numbers of the common 10-spot and 14-spot ladybirds and a number of other species, including the 11-spot, 22-spot, cream-spot, water and hieroglyphic ladybirds, Coccidula rufa, Rhyz

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Cezara Teodorescu
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14 views1 page

Aposematism Phenotypes Reflex Bleeding: Hippodamia Convergens

The atlas Ladybirds (Coccinellidae) of Britain and Ireland published in 2011[27] showed a decline of more than 20% in native species due to environmental changes and competition from foreign invaders. The distribution maps, compiled over a 20-year period with help from thousands of volunteers, showed a decline in the numbers of the common 10-spot and 14-spot ladybirds and a number of other species, including the 11-spot, 22-spot, cream-spot, water and hieroglyphic ladybirds, Coccidula rufa, Rhyz

Uploaded by

Cezara Teodorescu
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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The main predators of coccinellids are usually birds, but they are also the prey of frogs, wasps,

spiders, and dragonflies. The bright colours of many coccinellids discourage some potential
predators from making a meal of them. This phenomenon, called aposematism, works because
predators learn by experience to associate certain prey phenotypes with a bad taste. A further
defence, known as "reflex bleeding", exists in which an alkaloid toxin is exuded through the joints of
the exoskeleton, triggered by mechanical stimulation (such as by predator attack) in both larval and
adult beetles, deterring feeding.
Coccinellids in temperate regions enter diapause during the winter, so they often are among the first
insects to appear in the spring. Some species (e.g., Hippodamia convergens) gather into groups and
move to higher elevations, such as a mountain, to enter diapause.
Most coccinellids overwinter as adults, aggregating on the south sides of large objects such as trees
or houses during the winter months, dispersing in response to increasing day length in the spring. [25]
Predatory coccinellids are usually found on plants which harbour their prey. They lay their eggs near
their prey, to increase the likelihood the larvae will find the prey easily. In Harmonia axyridis, eggs
hatch in three to four days from clutches numbering from a few to several dozen. Depending on
resource availability, the larvae pass through four instars over 10–14 days, after
which pupation occurs. After a teneral period of several days, the adults become reproductively
active and are able to reproduce again later, although they may become reproductively quiescent
if eclosing late in the season. Total life span is one to two years on average. [26]

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