Most ladybirds are predators, and their primary food is aphids. A single seven-spot ladybird can devour dozens of aphids in a day, and over its lifetime the tally runs into the thousands. That reputation as a voracious garden hunter is well earned, but the full dietary picture is more varied than the aphid-eating cliché suggests. Some ladybird species eat scale insects or mites, others feed on fungal mildews, and a few are strict herbivores that gardeners consider pests. Even the classic aphid specialists supplement their diet with pollen, nectar, and occasionally each other.
Aphids Are the Main Course
The ladybird family (Coccinellidae) includes thousands of species worldwide, and the majority of the ones you encounter in a garden or on a farm belong to the aphid-feeding group. Aphids are soft-bodied, slow-moving, and tend to cluster in dense colonies on new plant growth, making them an ideal target for a beetle that hunts by walking along stems and leaves. Both larval and adult ladybirds feed on aphids, and the larvae are often even more aggressive feeders than the adults. Research on species like the seven-spot ladybird and its close relatives has shown that when aphids are abundant, larvae eat as much as they can, growing faster and developing more quickly than when prey is scarce.
That voracity scales with the larval stage. Early-stage larvae are small and eat relatively few aphids, but final-stage larvae can consume many times more per day. Studies of two common species found that both consumption rate and growth rate climbed sharply when prey was plentiful, and that larvae on a rich diet completed development faster than those on a restricted one.1Biological Control. Consumption, developmental and reproductive attributes of two con-generic ladybird predators under variable prey supply This makes intuitive sense: if you are a soft-skinned larva crawling through a world of ants, wasps, and birds, it pays to eat fast, grow fast, and reach adulthood as quickly as possible.
Beyond Aphids
Not all predatory ladybirds specialize in aphids. Several genera target scale insects, those small, armored or waxy creatures that cling to bark and stems. The ladybird Chilocorus bipustulatus, for example, prefers armored scales above all else, followed by soft scales and then mealybugs.2Entomologia Experimentalis et Applicata. Food Consumption of the Armored Scale Lady-Beetle Chilocorus bipustulatus (Coccinellidae) – Section: Abstract Scale-feeding ladybirds tend to have different body shapes and mouthparts than aphid specialists, reflecting the challenge of prying apart a scale insect’s protective covering.
Digesting scale insects also demands some extra help. Recent work on the ladybird Novius pumilus, which feeds on cottony cushion scales, found that gut bacteria play a meaningful role. Symbiotic microbes in the beetle’s digestive tract carry genes associated with breaking down hydrocarbons, fatty acids, and chitin, all components of the waxy shell that covers scale insects.3PubMed Central. Metabolism, digestion, and horizontal transfer: potential roles and interaction of symbiotic bacteria in the ladybird beetle Novius pumilus and their prey Icerya aegyptiaca The beetles appear to outsource part of their digestion to these bacteria, which is a neat trick for a predator that eats heavily armored prey.
Other ladybird species go after mites, whiteflies, or the eggs and larvae of other small insects. The dietary range across the whole family is broad enough that calling all ladybirds “aphid eaters” really only describes the most visible species in temperate gardens.
The Fungus Eaters
A whole tribe of ladybirds, the Halyziini, has largely abandoned the predatory lifestyle and feeds instead on powdery mildews. These are the small, often pale or orange ladybirds you might find on leaves dusted with white fungal growth. Both larvae and adults eat the mildew directly, and they occasionally supplement with sooty molds or pollen.4PLOS ONE. Olfactory Cues from Plants Infected by Powdery Mildew Guide Foraging by a Mycophagous Ladybird Beetle
These fungus-feeding ladybirds locate their food by smell. Plants infected with powdery mildew release volatile compounds, including a “moldy” chemical called 1-octen-3-ol that is characteristic of fungi. That compound alone was enough to attract the ladybirds in laboratory experiments.4PLOS ONE. Olfactory Cues from Plants Infected by Powdery Mildew Guide Foraging by a Mycophagous Ladybird Beetle If you grow squash, roses, or other plants prone to powdery mildew, you may have noticed these ladybirds congregating on the worst-affected leaves. They are not there for aphids; they are there for the fungus itself.
The evolutionary story here is fascinating. Genomic studies comparing ladybird lineages suggest that the ancestral diet of the family was fungivory, and that the aphid-eating habit evolved later as a transition from fungus feeding to full carnivory. A separate lineage then swung from carnivory back to herbivory.5PubMed Central. Molecular evolution of dietary shifts in ladybird beetles (Coleoptera: Coccinellidae): from fungivory to carnivory and herbivory So the fungus eaters are not oddball exceptions; they are closer to the original ladybird template, and the fierce aphid predators are the ones that branched off.
Herbivorous Ladybirds
The most infamous plant-eating ladybirds belong to the tribe Epilachnini. If you grow beans, squash, or aubergines, you may have encountered the Mexican bean beetle or the squash beetle, both of which chew on leaves and can cause real crop damage. These beetles look very much like their predatory relatives, round, spotted, and brightly colored, but their mandibles are adapted for scraping plant tissue rather than grabbing insects. They are a minority within the family, but in some regions they are significant agricultural pests.
The existence of herbivorous ladybirds surprises many gardeners, who assume every spotted beetle on their plants is a helpful predator. The easiest way to tell is by looking at the beetle’s surface texture and behavior: herbivorous species in the Epilachnini tend to have a distinctly fuzzy or downy appearance due to fine hairs, and they will be chewing on the leaf surface rather than patrolling for prey.
How Ladybirds Find Their Prey
Ladybirds do not simply stumble into aphid colonies by luck. They use a combination of chemical and visual cues to navigate toward food. One important signal is the alarm pheromone that aphids release when they are disturbed, a compound called (E)-β-farnesene. When a few aphids are picked off by a predator, the rest of the colony releases a burst of this chemical. Ironically, that alarm signal also attracts more ladybirds.
Research on the ladybird Hippodamia variegata identified a protein in the beetle’s antennae that binds strongly to (E)-β-farnesene and to several volatile chemicals released by the host plants aphids feed on. These plant volatiles and aphid pheromones together triggered strong antenna responses and attracted the beetles in behavioral tests.6PubMed. Antenna-Biased HvarOBP6 Coordinates Chemical Sense in Ladybug Hippodamia variegata to Aphid Alarm Pheromones and Habitat Plant Volatiles In short, ladybirds are eavesdropping on both the plants under attack and the aphids being eaten. The system is remarkably well tuned.
This chemical ecology has practical applications in agriculture. In Chinese apple orchards, researchers tested whether they could draw ladybirds toward target trees by deploying synthetic methyl salicylate, a volatile compound that plants produce when they are being damaged by herbivores. When these dispensers were placed among target trees and surrounded by companion plantings of calendula, ladybird numbers increased and aphid control improved.7Journal of Applied Ecology. Varying the spatial arrangement of synthetic herbivore-induced plant volatiles and companion plants to improve conservation biological control The ladybirds were attracted by the scent cue and then stayed because the companion plants offered pollen and nectar as supplementary food.
Pollen, Nectar, and Sugar Supplements
Even dedicated aphid hunters do not live on prey alone. Many ladybird species feed on pollen and nectar, especially in spring before aphid populations have boomed, or in late summer when aphid numbers crash. Flowering plants provide a bridging food source that keeps adult ladybirds alive and reproducing during lean periods.
Which plants work best? Olfactory preference tests with the harlequin ladybird showed that adults were strongly drawn to sunflower and dill among ten candidate companion plants, with both scent and color playing a role in the attraction.8Journal of Asia-Pacific Entomology. Visual and olfactory preference of Harmonia axyridis (Coleoptera: Coccinellidae) adults to various companion plants If you want to encourage ladybirds in your garden, planting dill, sunflowers, yarrow, and other open-flowered plants gives them a reason to stick around even when aphid numbers are low.
Cannibalism and Intraguild Predation
When food gets scarce, ladybirds turn on each other. Cannibalism is surprisingly common, especially among larvae. In laboratory studies of two aphid-feeding species, cannibalism rates rose sharply as aphid availability dropped, as density of larvae increased, and as size differences between individuals grew. Bigger larvae ate smaller ones, and newly hatched first-instar larvae were especially vulnerable in crowded conditions.9Biological Control. Larval cannibalism in aphidophagous ladybirds: Influencing factors, benefits and costs
Cannibalism is actually a rational survival strategy. A sibling egg or a smaller larva is a package of protein and fat that is easy to catch and safe to eat. Females often lay some infertile “trophic eggs” alongside fertile ones, providing an immediate first meal for newly hatched larvae. The calculation shifts when food is abundant: well-fed larvae have little reason to risk an encounter with a sibling that might fight back.
Intraguild predation, which is a more formal way of saying “eating other predators,” extends beyond siblings. Different ladybird species sharing the same plant will prey on each other’s eggs and larvae. This has become a serious ecological issue with the harlequin ladybird (Harmonia axyridis), an Asian species introduced around the world for biological pest control. The harlequin is bigger, more aggressive, and has an unusually broad diet. When harlequin larvae supplemented a limited aphid diet by eating eggs of the native two-spot ladybird, the harlequins developed better in every measurable way, while the two-spots gained no benefit from eating harlequin eggs in return.10Ecological Entomology. Effects of competition, cannibalism and intra-guild predation on larval development of the European coccinellid Adalia bipunctata and the invasive species Harmonia axyridis
Worse, the harlequin carries spores of a microsporidian parasite that does not harm the harlequin itself but is lethal to native ladybirds like the seven-spot. When native species eat harlequin eggs or larvae during intraguild predation, they ingest the spores and die.11PubMed. Invasive harlequin ladybird carries biological weapons against native competitors The harlequin is, in effect, carrying a biological weapon that punishes any competitor that tries to eat it. This is one reason harlequin populations have exploded while native ladybird numbers have declined in Europe and North America.
When Prey Fights Back
Not all aphids are easy meals. Some species accumulate toxic compounds from their host plants, and ladybirds that eat them pay a price. Larvae of the harlequin ladybird fed on the elder aphid (Aulacorthum magnoliae), which feeds on an elder plant known to contain toxic alkaloids, suffered higher mortality and grew more slowly than larvae fed on an ordinary potato aphid.12Entomological Science. Toxicity of the aphid Aulacorthum magnoliae to the predator Harmonia axyridis (Coleoptera: Coccinellidae) and genetic variance in the assimilation of the toxic aphids in H. axyridis larvae The toxicity came not from the aphids themselves but from whatever they had absorbed while feeding on the plant. In the wild, ladybirds probably learn to avoid or limit consumption of these defended prey items, but in a laboratory with no choice, the effects are dramatic.
A related concern has emerged with genetically modified crops. When two-spot ladybirds were fed aphids that had been feeding on transgenic potatoes engineered to produce a lectin for aphid resistance, the ladybirds’ egg production, egg viability, and lifespan all dropped over the following weeks. Female longevity decreased by up to half. The damage was reversible: once the beetles were switched back to aphids reared on normal plants, their reproduction recovered.13Molecular Breeding. Tri-trophic interactions involving pest aphids, predatory 2-spot ladybirds and transgenic potatoes expressing snowdrop lectin for aphid resistance This illustrates the concept of tri-trophic effects: a modification aimed at the plant’s relationship with its herbivore can ripple up the food chain to harm the predator you actually want to keep around.
Overwintering and Fat Reserves
In temperate regions, ladybirds enter a dormant state called diapause during winter, often clustering in large aggregations under bark, in leaf litter, or inside buildings. They do not feed during diapause. Instead, they survive on fat reserves built up during the autumn feeding period.
Preparing for diapause involves a metabolic shift. Research on the seven-spot ladybird found that genes related to fatty acid biosynthesis ramp up during the early stages of diapause induction, peaking during the first few weeks of dormancy, and then declining as winter progresses.14Frontiers in Physiology. Sequencing, Expression, and Functional Analyses of Four Genes Related to Fatty Acid Biosynthesis During the Diapause Process in the Female Ladybird, Coccinella septempunctata L. The beetles are essentially front-loading fat production so they have enough stored energy to last until spring. What triggers diapause is a combination of shortening day length, dropping temperatures, and in some species, the type of food available. Studies on another ladybird species found that the proportion of females entering diapause varied from as low as 5% to as high as 70%, with short days, low temperatures, and feeding on low-quality food all pushing more females into dormancy.15Journal of Applied Entomology. Photoperiodic, thermal and trophic responses of a predatory ladybird Cheilomenes propinqua
This matters for gardeners because a well-fed ladybird population going into autumn is more likely to survive the winter and re-emerge in spring. Gardens that provide late-season aphids and flowering plants give ladybirds the raw materials they need to pack on fat before the cold arrives.
Climate Change and the Feeding Balance
Warming temperatures affect both predator and prey, but not equally. Field experiments simulating a 2°C temperature increase in wheat fields found that aphid populations roughly doubled under warming, but ladybird densities did not increase to match. The field predation rate of harlequin ladybirds on aphids actually dropped by about a quarter under warmer conditions, partly because prey DNA degraded faster in the ladybirds’ guts at higher temperatures, making it harder to detect predation events using molecular analysis.16Functional Ecology. Increased ladybird predation and metabolism do not counterbalance increased field aphid population growth under experimental warming
In the laboratory, individual ladybird larvae actually ate more aphids at the warmer temperature: their functional response, meaning the rate at which they consumed aphids at different prey densities, increased by roughly half. But in the field, this individual boost was swamped by the much larger boom in aphid numbers.16Functional Ecology. Increased ladybird predation and metabolism do not counterbalance increased field aphid population growth under experimental warming The upshot is that each ladybird may eat more in a warmer world, but aphid populations will likely grow faster than ladybirds can keep up with. Gardeners and farmers who rely on ladybirds for natural pest control may find the balance shifting against them as average temperatures climb.
Mass Rearing and Artificial Diets
The commercial side of ladybird diets matters if you have ever bought ladybirds for release in a greenhouse or garden. Rearing millions of ladybirds on live aphids is expensive and logistically difficult, so researchers have spent decades developing artificial diets that can sustain ladybird colonies in the lab.
Modern artificial diets are formulated from ingredients like chicken liver powder, yeast, sugars, and various protein sources, blended and sometimes microencapsulated into tiny droplets that mimic the size and texture of prey items. Microencapsulated diets have shown promise for improving the stability and efficiency of mass rearing programs.17PubMed. Optimization and evaluation of microencapsulated artificial diet for mass rearing the predatory ladybird Propylea japonica (Coleoptera: Coccinellidae) At least one formulation achieved over 80% adult emergence in a species that had previously only been reared on live aphids, making large-scale production more feasible.18Journal of Asia-Pacific Entomology. Artificial diet development and its effect on the reproductive performances of Propylea japonica and Harmonia axyridis
The challenge is that ladybirds reared entirely on artificial diet often have lower reproductive output than those fed on live prey. Improving adult fecundity on artificial diets remains an active area of research, including work on optimizing nutrient ratios for the seven-spot ladybird.19Bulletin of Entomological Research. Improving the artificial diet for adult of seven spotted ladybird beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae) with orthogonal design For now, the most practical approach in commercial rearing facilities is to use artificial diet for the larval stages and then provide live or frozen prey, or at least supplementary natural food, to breeding adults. If you buy ladybirds from a supplier, the beetles may have been raised on a mix of artificial diet and real insect prey, and releasing them into a garden where actual aphids are available gives them the best chance of settling in and reproducing.
Attracting Ladybirds to Your Garden
Understanding what ladybirds eat makes it straightforward to design a garden that supports them. The core requirement is prey: if you have aphids, you will have ladybirds eventually. Avoiding broad-spectrum insecticides is the single most important step, since these kill ladybirds along with everything else.
Beyond that, companion planting helps by providing pollen and nectar during the gaps when aphid numbers are low. Sunflowers and dill are especially attractive based on both scent and color preferences.8Journal of Asia-Pacific Entomology. Visual and olfactory preference of Harmonia axyridis (Coleoptera: Coccinellidae) adults to various companion plants Yarrow, tansy, goldenrod, and dandelions are also good candidates. The goal is not to eliminate aphids entirely but to maintain a garden ecosystem where prey and predator coexist. A small population of aphids in spring feeds the first generation of ladybird larvae, which then keeps the aphid population in check through summer. Removing every aphid with pesticides at the first sign of them removes the food supply that your predators need to establish.
Leaving some leaf litter and undisturbed corners through winter also gives ladybirds somewhere to shelter during diapause. A tidy garden swept clean in autumn is a poor habitat for overwintering beetles. The messy bits, the dead stems, the pile of leaves behind the shed, are exactly where clusters of dormant ladybirds ride out the cold months before emerging hungry in spring.