Insects carry pollen from flower to flower allowing pollination and consequent fruit formation. In general, flowering insects have morphological characters suitable for their specialization: the most common are the body thickly covered with bristles and the sucking or licking-sucking mouthparts.
The first character means that the pollen remains trapped between the bristles and can thus be transported from flower to flower; the second is an adaptation to the diet of these insects, based on sugary liquids, represented in particular by the nectar of flowers.
Some insects have more marked specializations. For example, in the Apoidea, the tibiae of the hind legs are dilated and have an external concavity, called cestella, in which the pollen collected and held in a globular mass by bristles arranged along the edge of the cestella accumulates.
Another organ present in the Apoidea is the brush, a formation of sturdy bristles on the hind legs, which the insect uses to brush the body and collect pollen. But why do some insects choose flowers? The article: How do insects choose flowers? A review of multi-attribute flower choice and decoy effects in flower-visiting insects, published on the The Journal of animal ecology, gives very interesting answers.
We can read: "Understanding why animals (including humans) choose one thing over another is one of the key questions underlying the fields of behavioural ecology, behavioural economics and psychology. Most traditional studies of food choice in animals focus on simple, single-attribute decision tasks.
However, animals in the wild are often faced with multi-attribute choice tasks where options in the choice set vary across multiple dimensions. Multi-attribute decision-making is particularly relevant for flower-visiting insects faced with deciding between flowers that may differ in reward attributes such as sugar concentration, nectar volume and pollen composition as well as non-rewarding attributes such as colour, symmetry and odour.
How do flower-visiting insects deal with complex multi-attribute decision tasks? Here we review and synthesise research on the decision strategies used by flower-visiting insects when making multi-attribute decisions. In particular, we review how different types of foraging frameworks (classic optimal foraging theory, nutritional ecology, heuristics) conceptualise multi-attribute choice and we discuss how phenomena such as innate preferences, flower constancy and context dependence influence our understanding of flower choice.
We find that multi-attribute decision-making is a complex process that can be influenced by innate preferences, flower constancy, the composition of the choice set and economic reward value. We argue that to understand and predict flower choice in flower-visiting insects, we need to move beyond simplified choice sets towards a view of multi-attribute choice which integrates the role of non-rewarding attributes and which includes flower constancy, innate preferences and context dependence.
We further caution that behavioural experiments need to consider the possibility of context dependence in the design and interpretation of preference experiments. We conclude with a discussion of outstanding questions for future research. We also present a conceptual framework that incorporates the multiple dimensions of choice behaviour."