Coccinellidae function in
complex food webs as predators, as consumers of non-prey
foods, and as prey or hosts of natural enemies. Dietary
breadth and its implications remain largely unexplored.
Likewise the nature and implications of interactions
with other predators in the field are poorly understood.
The use of biochemical tools based on nucleic acids,
proteins, sugars and other components of coccinellid
diets, expands our understanding of their trophic
ecology – but only under field conditions in which
coccinellids live, reproduce, forage, and consume prey
(including intraguild prey), pollen, fungi, nectars, and
other foods. We review the various methods which have
been applied to the study of trophic relationships
involving the Coccinellidae, their advantages and
disadvantages, and some salient innovations and results
produced by the range of technologies and their
combinations. We advocate employing multiple tools to
generate a more complete picture of the trophic ecology
of a predator. The false perceptions of the strength and
direction of trophic linkages that can result from a
methodologically narrow approach is well illustrated by
the laboratory and field assessments of coccinellids as
intraguild predators, a phenomenon that is discussed in
detail here. Assessing intraguild predation, and the
breadth of prey and non-prey foods of the Coccinellidae,
is essential to the understanding of this group, and for
their application as biological control
From a survey of 30
species and varieties of ladybugs the presence of
alkaloids appears to be correlated with the existence of
aposematic colour and not with being carnivorous or
phytophagous. The alkaloids described until now all
belong to the Coccinellini and are closely related, but
other types of bases have been detected in some genera.
The observed distributions are in agreement with the
modern taxonomy of the family.
Ladybug alkaloids constitute an effective defence
against ants, Myrmica
rubra, and quails, Coturnix coturnix, but
all the beetles containing alkaloids do not possess the
same degree of protection. Individual quail react
differently towards moderately protected species.
The bioassay used for the first isolation of
coccinelin is described. The repulsive activities of
aqueous solutions of coccinellin and convergin towards
ants have been compared.