Ladybug larvae, often mistaken for tiny, black-and-orange alligators, are the immature stage of the familiar garden beetle. Successfully raising these beneficial insects requires a consistent and abundant food supply to support their demanding developmental cycle.
The Ladybug Larva’s Natural Menu
In natural settings, the primary diet for ladybug larvae consists of soft-bodied insects like aphids, mealybugs, and scale insects. This preference is due to the high protein content and the ease with which the larvae can puncture the soft exoskeletons of these pests. A constant supply of live prey ensures the larvae receive all the necessary nutrients for growth and pupation.
The predatory capacity of a single larva is significant throughout its developmental period, which typically lasts between two and four weeks. During this time, a single larva may consume several hundred aphids, sometimes upwards of 400 or 500. This intense feeding phase underscores the need for a continuous food source when rearing them.
Larvae also commonly feed on insect eggs and mites, which are readily available on plants infested with pests. This varied diet ensures they receive a balanced intake of amino acids and fats necessary to form a healthy adult beetle. The goal of the larva is simply to consume as much as possible before it transitions into the non-feeding pupal stage.
Supplemental Diets for Rearing
When raising ladybug larvae in controlled environments or when natural prey is insufficient, entomologists often turn to scientifically formulated supplemental diets. These alternatives are designed to mimic the nutritional profile of live insects, primarily focusing on high protein content.
One common substitute involves non-viable insect eggs, such as those from the Mediterranean flour moth (Ephestia kuehniella). These moth eggs provide an excellent, easily digestible source of protein and fat, often used commercially to rear large colonies of ladybugs. The eggs are typically frozen or sterilized to prevent them from hatching, ensuring they are purely a food source. This controlled protein source helps eliminate the need for constantly sourcing live aphids.
Agricultural researchers also utilize a mixture of nutritional yeast and pure pollen as a dietary supplement. Brewer’s yeast is rich in B vitamins and protein, while pollen provides necessary lipids and micronutrients. When mixed with a small amount of water or honey, this combination forms a nutritionally dense paste suitable for larval consumption.
In situations where immediate protein is needed, some rearing protocols have historically included highly concentrated protein sources like ground beef or liver. While less common now due to contamination and spoilage risks, these meats offer a high concentration of amino acids.
These supplemental foods are generally used to sustain the larvae through the early instars until a fresh supply of live prey becomes available. The purpose of using these alternative foods is to prevent cannibalism, which occurs when larvae are starved, and to ensure they gain enough mass to complete the final molt into the pupal stage.
Preparation and Delivery of Food
Presenting the supplemental diet in a format the larvae can consume requires careful preparation, as they cannot easily chew dry powders or large chunks of material. The non-live ingredients, such as yeast or pollen, must first be mixed with a small amount of distilled water or a honey solution to create a thick, spreadable slurry. The consistency should be manageable enough to hold its shape without drying out too quickly.
This prepared paste is then applied to the rearing container walls or placed onto a small, clean piece of wax paper or a dry leaf. It is important to apply the food in small, distinct droplets rather than a large smear, which helps prevent the larvae from becoming trapped in the sticky substance. The food must be easily accessible but separate from the substrate.
Maintaining a high standard of hygiene within the rearing container is paramount, especially when using moist, high-protein supplemental diets. The paste should be replaced daily, or at least every 24 hours, to prevent the growth of harmful molds and bacteria. Spoiled food poses a significant risk to the larvae and can rapidly contaminate the entire colony.
When feeding a dry, non-prey diet, providing a source of hydration becomes particularly important for larval health. This is typically accomplished by placing a small piece of clean cotton or sponge, lightly moistened with water, into the container. The cotton provides surface area for the larvae to drink without the risk of drowning in standing water.
This hydration source must also be monitored to ensure it remains moist but not saturated, avoiding overly damp conditions that promote fungal growth. Proper food delivery and sanitation practices maximize the survival rate of the ladybug larvae.