Cicada Biological Cycle and Ecological Management in Arboreal Ecosystems

Biological Cycle and Mass Emergence of Cicadidae

The presence of cicadas, known in some regions as chicharras, is a seasonal phenomenon that generates both fascination and concern in the field of arboriculture. These insects, with their characteristic song, are an intrinsic part of many ecosystems, but their life cycle can significantly influence tree health, especially in urban and rural environments across Argentina and Latin America.

The life cycle of cicadas exhibits a remarkable peculiarity, dominated by a prolonged subterranean phase. This process begins when the female deposits her eggs in small incisions made in young branches of trees and shrubs. After hatching, the nymphs fall to the ground and burrow, commencing their most extended stage, which can last from a few years (in annual species) to 13 or 17 years (in periodical species). Underground, the nymphs feed on the sap of tree roots, extracting nutrients with their piercing-sucking mouthparts. This subterranean development culminates when the mature nymphs emerge, generally in spring or summer, to transform into adults. The adult phase is brief, dedicated to reproduction, and it is during this period that their distinctive song becomes most audible. This pattern of mass emergence of periodical cicadas, though infrequent, represents a large-scale ecological event, as observed in historical outbreaks across various latitudes.

Physiological Impact of Oviposition on Arboreal Branching

The impact of cicadas on trees manifests primarily in two ways: through oviposition and feeding. The egg-laying by adult females involves making multiple longitudinal cuts in tender branches. These damages can lead to the death of branch tips, a phenomenon known as “tip dieback” or “flagging,” and in severe cases, the breakage of young branches. While mature trees usually recover from these aesthetic damages, young or newly transplanted specimens, as well as fruit trees, can suffer considerable stress, affecting their growth and production. The feeding of nymphs on the roots, although constant for years, rarely causes the death of the tree in its adult phase, as sap extraction is distributed among multiple points and is not usually intense enough to compromise the vitality of a well-established root system. However, in trees already weakened by other causes (drought, diseases, poor soils), sap suction can aggravate their general condition.

The management of cicada populations falls under the principles of Integrated Pest Management (IPM), prioritizing ecosystem health. One of the most effective strategies to protect young and ornamental trees during periods of mass emergence is the application of fine mesh or protective netting around the trunk and main branches, which prevents oviposition. In the context of ecosystem sustainability and resilience, fostering biodiversity in the garden attracts natural predators of cicadas, such as birds, wasps, and small mammals, which help regulate their populations. Selecting native tree species and establishing them correctly in suitable sites reduces overall plant stress, making them more resistant to oviposition damage. Recent studies in agroecology suggest that soil health and microbial vitality can influence root resistance to nymph feeding, although further research is needed in this area. For ornamental or high-value trees, selective pruning of branches with severe oviposition damage is considered to promote healthy new growth, always outside the insect emergence period.

Mitigation Strategies and Biological Control of Cicadidae

Contemporary research on cicadas focuses on better understanding the factors that trigger their periodic outbreaks and how climate change might influence their distribution and frequency. Advanced predictive models are being developed to anticipate mass emergences, allowing arborists and green space managers to prepare in advance. There is growing interest in the ecological role of cicadas beyond their negative impact, recognizing them as a food source for fauna and as ecosystem engineers that aerate the soil during their emergence. The University of Buenos Aires, through its agronomy faculties, has conducted studies on the distribution of various cicada species in the Pampas region and their interaction with crops and forestations. Furthermore, new tree varieties with greater innate resistance to oviposition damage are being explored, seeking long-term solutions that minimize chemical intervention. Permaculture, for its part, advocates for the creation of resilient systems where imbalances caused by insects like cicadas are mitigated by the diversity and structure of the ecosystem itself. A recent example of an innovative approach includes remote monitoring of cicada activity using acoustic sensors, a technique that offers valuable data for managing large forest areas. Source: INTA Argentina on Forest Health and Source: Infojardín on Tree Care

In summary, understanding the cicada life cycle is fundamental to mitigating their impact on trees. While their presence is part of natural dynamics, applying integrated management strategies and promoting arboreal resilience are key to maintaining the health of our forest and urban ecosystems. Observation and knowledge are the most valuable tools for coexisting harmoniously with these fascinating insects, ensuring the vitality of our region’s flora.