Beneficial Bugs - Ladybugs

This installment of beneficial bugs is going to talk about members of the family Coccinellidae, the ladybugs. Although we call them ladybugs here in the US, they go by many different names worldwide, including lady birds, ladybird beetles, and lady beetles. The most accurate of these names is the ladybeetle, as these insects are not true bugs (those are in a different order entirely) they are beetles, from the order Coleoptera. Nevertheless, we shall stick with ‘ladybugs’ as that is the most common colloquial name for those of us living in Virginia. 

There are more than 6,000 described species of ladybug found all over the world and most are found to have conspicuous aposematic (‘warning’) coloring (usually red and black; Fig. 1) and patterns. This coloration serves as a warning to potential predators that their blood is full of distasteful, toxic alkaloids, azamacrolides, pyrazines, and polyamines. Interestingly, ladybugs also exhibit a defensive tactic known as reflex bleeding, which is the deliberate excretion of hemolymph (insect blood) from their knee joints (Fig. 2). This may seem like a strange reaction to have in response to predator pressure but remember — it is the blood that is distasteful, so it is a benefit to the ladybug to make predators aware of this before biting them. 

Figure 1. A ladybug cluster displaying the typical red and black coloration. Photograph © The Real Estreya. (flickr) 

Figure 2. Spotless Lady Beetle (Cycloneda sanguinea) reflex bleeding - the orange drop is hemolymph (insect blood). Photograph © stevenw12339. (flickr) 

In temperate climates, like we have here in Virginia, the life cycle is similar across species; they typically start breeding in late spring (soon!) through early summer. For the most part they have promiscuous breeding, so individuals are indiscriminate in mate choice. They have complete metamorphosis (holometabolism), meaning they start out as eggs, hatch into larva, then pupate for some length of time before emerging as an adult. 

Generally, the eggs are bright yellow, clustered, and laid vertically (Fig. 3). Once the larvae (Fig. 4) hatch, they begin eating and growing and typically go through four stages of growth (instars) and molt three times before pupating (Fig. 5). Upon emergence from the pupa the adults can live up to a year. 

Figure 3. Ladybug eggs. Photograph © Tom Lee. (flickr) 

Figure 4. Seven-spotted Lady Beetle (Coccinella septempunctata) larva. Photograph © Tom Lee. (flickr)  

Figure 5. Seven-spotted Lady Beetle (Coccinella septempunctata) pupa. Photograph © Gilles San Martin. (flickr) 

Ladybug diets vary, though most species are carnivorous as larvae and as adults and prey on insects, including plant pests like aphids, thrips, whiteflies, and scale insects (Fig. 6). It is this diet that has earns them the badge of a beneficial insect. Several species have been introduced outside of their natural range for use as biological control agents and although some of these programs have been successful others have been disastrous, as some species have been found to attack agricultural crops and infest homes. The Asian ladybeetle (Harmonia axyridis) was introduced as a control agent and has, by many accounts, been quite successful in this role. However, it has also become a bit of a nuisance to humans and a threat to our native species. The Asian Ladybeetle has a voracious appetite (hence their selection as a control agent) that enables them to outcompete and even consume our native species. Additionally, this species also carries a parasite to which it is immune but that easily infects and kills native species. 

Figure 6. Cheilomenes sexmaculata ladybugs feeding on Oleander aphids (Aphis nerii) while mating. Several early larval instars can be seen also feeding on aphids. Photograph © budak. (flickr) 

It is still possible to add to the native complement in your garden by purchasing individuals and introducing them, however I urge you to be absolutely certain that you are ordering a species native to Virginia. In truth, I would discourage this behavior, as it is preferential to improve your current habitat and encourage the establishment of native species. As most species augment their diet with leaves, pollen, sap, fungi, and honeydew, you can plant flowers/plants that provide abundant pollen and nectar and have a good-sized area upon which they can land to feed. Additionally, it is important to consider whether the habitat will support their dormancy over the winter; they tend to overwinter under leaves or nestled in bunches of grass, so make sure you just let all those leaves and dead plants stay in your garden — you will find that native bees use them for nesting too. You also need to be able to handle some level of pest presence, because you need to have enough food for the ladybugs to stay — once the food is gone, so are they, and it’s difficult to get them to come back. Lastly, you need to avoid pesticides, not only is it harmful to the ladybugs themselves but also to their prey and, like I said, they need those prey insects. So that’s about it, hopefully these tips will help you have lots more ladybugs in your gardens this year!

Read more articles in the Spring 2025 CSWCD Newsletter.