Beneficial Bugs - Soldier Beetles

When people think of beneficial insects, bees and ladybugs often steal the spotlight. Yet quietly at work in fields, gardens, and meadows is another valuable ally: the soldier beetle. Often mistaken for fireflies or dismissed as just another small beetle, soldier beetles provide important ecosystem services throughout their entire life cycle—both as larvae and as adults.

Soldier beetles belong to the family Cantharidae and are sometimes called leatherwing beetles because of their soft, flexible wing covers. They are commonly found on flowers, grasses, and low vegetation during late spring and summer. Unlike many insects that are beneficial only in one stage of life, soldier beetles contribute positively to ecosystems from larva to adult.

Beneficial Larvae: Pest Control in the Soil

The larval stage (Fig. 1) of soldier beetles is spent mostly out of sight, but their impact is significant. Soldier beetle larvae live in soil, leaf litter, and under debris, where they act as voracious predators.

Figure 1. Soldier beetle larva – small and rarely seen. Photograph © Judy Gallagher. (flickr)

Their primary ecological role at this stage is biological pest control. Larvae feed on a wide variety of soft-bodied pests, including:

• Aphids

• Caterpillars

• Fly larvae

• Beetle eggs

• Slugs and snails

By preying on these organisms, soldier beetle larvae help regulate pest populations before they reach damaging levels. This reduces the need for chemical pesticides, supporting healthier soils and less polluted waterways. Additionally, their movement through soil and leaf litter contributes modestly to soil aeration and nutrient cycling, helping organic matter break down and improving soil structure.

Figure 2. Life cycle of a soldier beetle.

Beneficial Adults: Pollinators and Predators

As adults, the extremely diverse (Fig. 3) soldier beetles emerge as active participants in above-ground ecosystems. They are most commonly seen on flowers, where they feed on pollen and nectar. In doing so, they provide an often-overlooked but valuable service: pollination.

While they are not as specialized or efficient as bees, soldier beetles visit a wide range of flowering plants, including wildflowers, herbs, and some crops. Their frequent movement between blooms helps transfer pollen, contributing to plant reproduction and biodiversity.

Adult soldier beetles also continue their role as predators. Along with pollen and nectar, they consume aphids, small insects, and insect eggs. This dual diet allows them to support both plant health and pest suppression simultaneously.

Figure 3. Soldier beetle diversity. 3a. Adult soldier beetle (Atalantycha billneata) (flickr). 3b. Adult soldier beetle. (flickr). 3c. Adult soldier beetle (Podabrus rugosulus). (flickr). 3d. Adult soldier beetle (Podabrus tomentosus). (flickr). All photographs © Judy Gallagher.

Ecosystem Services Provided by Soldier Beetles

Across both life stages, soldier beetles offer multiple ecosystem services that benefit natural and human-managed landscapes:

•   Biological pest control - they reduce populations of harmful insects without chemicals.

•   Pollination - they support flowering plants and overall biodiversity.

•   Soil health - they aid decomposition and nutrient cycling during the larval stage.

•   Food web support - they serve as prey for birds, amphibians, and other beneficial insects.

Because they are active in different habitats and at different times of the year, soldier beetles help stabilize ecosystems by filling multiple ecological roles. From pest-eating larvae hidden beneath the soil to pollen-carrying adults visiting your flowers (Fig. 4), they provide continuous benefits throughout their lives.

Figure 4. A pair of mating Goldenrod Soldier Beetle (Chauliognathus pensylvanicus). Photograph © Judy Gallagher. (flickr)

Rather than viewing all beetles as pests, understanding the role of soldier beetles reveals a more nuanced picture—one in which small, often unnoticed insects play an outsized role in maintaining ecological balance.

In a time when insect populations are declining worldwide, recognizing and supporting beneficial insects like soldier beetles is increasingly important. They thrive in diverse, pesticide-free environments with native plants, leaf litter, and undisturbed soil. Gardens and landscapes that welcome soldier beetles often enjoy healthier plants, fewer pest outbreaks, and increased pollinator activity.  By supporting soldier beetles and other beneficial insects, we strengthen the ecosystems that sustain our gardens, farms, and wild spaces alike.