What Do Red-Eyed Cicadas Eat? Dietary Habits Explained

Cicadas are fascinating insects known for their distinctive sounds and unique life cycles. Among the diverse cicada species, red-eyed cicadas stand out due to their striking red eyes and intriguing habits. Understanding what red-eyed cicadas eat can provide insight into their ecological roles and behavior. This article explores the dietary habits of red-eyed cicadas in detail, shedding light on what fuels these remarkable insects throughout their lives.

Introduction to Red-Eyed Cicadas

Red-eyed cicadas belong to a subgroup of cicadas that feature vivid red eyes, making them easily recognizable compared to other species with black or brown eyes. These insects are primarily found in various regions across North America and parts of Asia. Like all cicadas, they undergo a long underground nymph phase before emerging as adults.

Their life cycle is characterized by periodic mass emergences, during which millions of adults appear simultaneously, creating a spectacular natural phenomenon. The red-eyed variety is no exception, participating in these mass emergences and captivating observers with their appearance and behavior.

Cicada Anatomy and Feeding Mechanism

Before diving into the specific diet of red-eyed cicadas, it is important to understand how cicadas feed generally. Cicadas possess specialized mouthparts called proboscises—elongated, needle-like structures used to pierce plant tissue and suck fluids.

This feeding apparatus is perfectly adapted for extracting sap from plants, particularly from tree xylem or phloem. The ability to tap into these nutrient-rich fluids allows cicadas to sustain themselves during all life stages.

What Do Red-Eyed Cicadas Eat?

Nymph Stage Diet: Root Sap Feeding

The dietary habits of red-eyed cicadas vary significantly between their nymph and adult stages.

• Nymphs live underground for most of their lives, feeding primarily on the sap extracted from tree roots.
• They use their sharp mouthparts to pierce rootlets of various trees and shrubs.
• The nymphs rely heavily on xylem fluid—the water and mineral-rich fluid transported from roots to leaves—to nourish themselves during this extended subterranean developmental phase.

This diet sustains the nymphs for years or even over a decade depending on the species, as they slowly grow and mature beneath the soil. Because root sap is less nutrient-dense than other plant fluids, nymphs must consume large quantities over time to accumulate enough energy for metamorphosis.

Adult Stage Diet: Continued Sap Feeding from Tree Branches

Once red-eyed cicada nymphs emerge from the soil, molt into adults, and begin their above-ground life phase, they continue feeding on plant sap—but the source shifts:

• Adult red-eyed cicadas feed on xylem sap from twigs, branches, and stems rather than roots.
• They insert their proboscis into woody parts of trees or shrubs to access this sap.
• Common host plants include oak, maple, elm, hickory, and other deciduous trees native to their habitat range.

Although adults do feed actively during their short above-ground lifespan (typically 4-6 weeks), they do not consume solid food or leaves. Their diet consists almost exclusively of plant fluids.

Importance of Xylem Sap in Their Diet

Xylem sap differs from phloem sap in composition—it carries water and dissolved minerals upward from roots but contains relatively low levels of sugars and organic nutrients compared to phloem sap. Despite this low nutritional value, cicadas have evolved physiological adaptations allowing them to efficiently process large volumes of xylem fluid.

This adaptation explains why cicadas spend much of their lifecycle consuming sap rather than more nutrient-rich plant parts. Their unique digestive system helps extract suitable nourishment while expelling excess water.

Do Red-Eyed Cicadas Feed on Specific Plants?

Red-eyed cicadas are considered polyphagous, meaning they feed on multiple tree species rather than specializing in one particular kind. However, they do show preferences influenced by availability and habitat:

• They tend to select hardwood trees common in temperate forests within their range.
• Oak species (Quercus spp.) are often favored due to abundant sap flow and widespread distribution.
• Maples (Acer spp.) and elms (Ulmus spp.) also serve as frequent hosts.
• Occasionally, they may feed on fruit trees or ornamental plants if these are present in their environment.

The flexibility in host plant selection contributes to their successful survival across diverse ecosystems.

Feeding Behavior and Impact on Host Plants

Mild Impact but Generally Non-Damaging

Despite feeding on plant sap for long periods, red-eyed cicadas tend not to cause significant harm to host plants:

• Their piercing mouthparts are fine enough that feeding wounds rarely result in serious damage.
• The volume of sap removed is usually insufficient to affect tree health noticeably.
• Trees are well-adapted to tolerate such minor stress without decline.

Egg Laying Can Cause Damage

While feeding itself is mostly harmless, female red-eyed cicadas cause localized damage when laying eggs:

• Females use a specialized ovipositor to slice small slits into thin branches or twigs.
• Eggs are deposited within these slits.
• This activity can cause “flagging,” where affected branches die back or break off prematurely.

However, this damage is typically limited in scope and does not threaten mature trees except in cases of very heavy infestations.

Nutritional Adaptations of Red-Eyed Cicadas

Surviving on a diet based largely on watery xylem sap requires several remarkable adaptations:

1. Water Processing: Cicadas consume vast amounts of xylem fluid but excrete excess water rapidly through specialized glands called Malpighian tubules.
2. Symbiotic Bacteria: Many cicada species harbor symbiotic microorganisms inside specialized organs called bacteriomes. These bacteria help synthesize essential amino acids and vitamins lacking in the xylem sap.
3. Efficient Digestion: The insect gut is adapted for filtering nutrients efficiently while passing large volumes of fluid quickly.

Together, these physiological traits allow red-eyed cicadas to thrive on an otherwise nutritionally poor food source.

Seasonal Variations in Feeding Activity

Adult red-eyed cicadas exhibit peak feeding activity during warm months—late spring through summer—coinciding with their emergence:

• Sap flow within host plants is highest during this period due to active transpiration.
• Warmer temperatures increase insect metabolism, prompting more frequent feeding bouts.

Nymphs underground maintain relatively steady feeding year-round but slow down during colder months when root activity decreases.

Conclusion

Red-eyed cicadas have specialized dietary habits centered around consuming plant sap throughout both nymphal and adult stages. Underground nymphs feed on root xylem fluids for most of their long development period before emerging as adults to feed on twig xylem sap above ground.

Their ability to extract sufficient nutrients from watery xylem fluid is enabled by remarkable physiological adaptations including symbiotic bacteria and efficient water management systems. Though they feed on a wide variety of hardwood trees without causing substantial harm through feeding alone, egg-laying can occasionally result in localized branch damage.

Understanding what red-eyed cicadas eat highlights their important role in forest ecosystems as specialized herbivores with unique life strategies. Their dietary habits reflect fascinating evolutionary solutions allowing survival on an unconventional food source while supporting spectacular mass emergences witnessed by many nature enthusiasts worldwide.