May Beetles and Junebugs

Melolonthinae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Scarabaeoidea
Family: Scarabaeidae
Subfamily: Melolonthinae

Pronunciation

How to pronounce Melolonthinae: /ˌmɛloʊˈlɒnθɪniː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

American Rose Chafer - Macrodactylus subspinosus (51232670088) by Christina Butler from Georgia, United States. Used under a CC BY 2.0 license.

Western Rose Chafers (37008085092) by Katja Schulz from Washington, D. C., USA. Used under a CC BY 2.0 license.

Hoplia trivialis by Jacy Lucier. Used under a CC BY-SA 4.0 license.

Macrodactylus subspinosus 5138010 by Susan Ellis, , Bugwood.org. Used under a CC BY 3.0 us license.

Dusty June Beetle imported from iNaturalist photo 291551073 on 7 August 2024 by (c) Cricket Raspet, some rights reserved (CC BY). Used under a CC BY 4.0 license.

Monkey Beetle - Hoplia dispar, Packer Lake, California by Judy Gallagher. Used under a CC BY 2.0 license.

Summary

Melolonthinae, or May Beetles and Junebugs, are a diverse subfamily of scarab beetles with over 11,000 species globally. They are medium to large size, commonly brown or black, and play significant ecological and economic roles yet are also notable pests in agriculture.

Physical Characteristics

Melolonthinae adults range from 3 to 58 mm in length, usually brown or black in colour. They may be shiny or covered in setae or scales. The clypeus is not armed with teeth, with two antennae comprising 7 to 10 segments that form a club. The scutellum is exposed, and the margins of the elytra are straight. Legs end in toothed or double tarsal claws.

Identification Tips

Distinguishable by their characteristic C-shaped larvae with a darker well-sclerotised head and specific antennal features. Adult males have larger fingered antennae compared to females.

Habitat

Found worldwide, including across North America, inhabiting soil for larval stages and above ground environments for adults.

Distribution

Widespread distribution across most of the world, with a significant presence in North America.

Diet

Larval melolonthines feed on plant roots and humus, with known host plants including grasses, clover, and sugarcane. Adults may feed on tree leaves, flowers, or pollen, but some do not feed at all.

Life Cycle

Life cycle includes four stages: egg, larva, pupa, and adult. The larval stage can last up to two years, while the adult stage is short, typically lasting only a few days to weeks.

Reproduction

Eggs are laid in the soil, where the larval and pupal stages occur. Mating behavior is characterized by the attraction to pheromones emitted by virgin females in non-feeding species.

Ecosystem Role

Melolonthinae play roles in soil aeration (larvae) and may influence plant health as pest or pollinator species (adults).

Economic Impact

Some species are economically significant pests, particularly in agriculture, affecting crops like sugarcane, corn, and various fruits.

Cultural Significance

Widely featured in folklore, especially species like Amphimallon, Phyllophaga, and Polyphylla associated with the 'June beetles' or cockchafers.