Lily flowers are notoriously rampant producers of nectar, which is a sugary fluid that plants secrete to attract pollinators. Pollinators are animals that transfer pollen from flower to flower, fertilizing plants and triggering their reproductive cycles. In addition to attracting these helpful pollinating animal species, however, flowers in the lily family, Liliaceae, can also attract harmful species.
Lilies and day lilies -- which have large red, orange or yellow flowers that only last for one day -- both attract hummingbird species. More than 300 species of hummingbirds exist, all of which are in the Western Hemisphere and the majority are in Central and South America. Several hummingbird species, however, such as the Rufous hummingbird (Selasphorus rufus), inhabit North America and you could potentially attract them to your yard or garden using lilies.
Like hummingbird species, the bright colors and rich nectar contents of lily flowers attract butterflies. Some common butterfly species that you could potentially see flying around or perched on lilies include common wood nymphs (Cercyonis pegala), monarch butterflies (Danaus plexippus) and viceroy butterflies (Limenitis archippus), the latter of which closely resembles a monarch in appearance. For best results attracting butterflies, the University of Illinois suggests that you plant lilies in large groups, as opposed to in small patches.
Unlike other pollinators of lily flowers, bees are unable to see the color red. For this reason, the majority of bee species, such as western honey bees (Apis mellifera) and common eastern bumble bees (Bombus impatiens) are attracted to yellow flowers. Flowers in the lily family that are able to attract bees include lemon day lilies (Hemerocallis lilio-asphodelus), yellow fawn lilies (Erythronium grandiflorum) and cat's ear (Calochortus luteus or monophyllus).
Bulb Fly Species
Unlike hummingbirds, butterflies and bee species, which enjoy symbiotic relationships with the lily flowers that attract them, bulb fly species can be detrimental to health of lily flowers. In addition to feeding on the nectar of lily flowers, bulb flies lay their eggs on the flowers. The resulting larvae, known as maggots, feed on plant tissues and can stunt the growth of lilies or cause other deformities. Narcissus bulb flies, which include the species Eumerus strigatus, Eumerus tuburculatus and Merodon equestris, are the bulb flies that most commonly infest lily flowers.
Thrips are tiny, typically black-winged insects that can be serious pests for ornamental flowers, including lilies. Like bulb fly larvae, thrips feed on plant tissues and can cause leaf scarring and other damage. The thrip species that most commonly invade lily flowers include lily bulb thrips (Liothrips vaneeckei priesner), banded greenhouse thrips (Hercinothrips femoralis) and western flower thrips (Frankliniella occidentalis).