Microlarinus lareynii

(Jacquelin du Val, 1852)

Puncturevine seed weevil

Microlarinus lareynii is a seed-feeding weevil in the Curculionidae, native to the Mediterranean region and India. It was introduced to North America in the early 1960s as a agent for puncturevine (Tribulus terrestris), an weed. The exhibits strong specificity, with larvae developing exclusively within the seeds of its target host plant. Despite its potential for high reproductive output, field success in controlling weed has been variable due to climatic and biological mismatches with the host plant.

Microlarinus lareynii by (c) Catherine C. Galley, some rights reserved (CC BY), uploaded by Catherine C. Galley. Used under a CC-BY license.

Microlarinus lareynii by USDA ARS European Biological Control Laboratory. Used under a CC BY 3.0 us license.

Pronunciation

How to pronounce Microlarinus lareynii: /ˌmaɪ.kroʊˌlɑːˈraɪ.nəs ləˈreɪ.ni.aɪ/

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

Identification

Distinguished from the related stem-feeding weevil Microlarinus lypriformis by its seed-feeding ; may be found on puncturevine plants but positive identification requires examination of larval feeding damage within seeds or expert taxonomic verification. The two Microlarinus are often used together in programs, with M. lareynii targeting seeds while M. lypriformis targets stems.

Images

Appearance

Small weevil with characteristic elongated snout typical of Curculionidae. Specific morphological details not well-documented in available sources.

Habitat

Open, sunny, disturbed areas where puncturevine (Tribulus terrestris) occurs, including roadsides, waste places, and agricultural fields. Associated with plant presence rather than specific abiotic conditions.

Distribution

Native to interior regions of Italy, France, and Rajasthan, India. Introduced to the United States (California, Arizona, and other states) and Canada for purposes. Established present in Hawaii and the conterminous 48 United States.

Seasonality

Multiple per year in favorable climates; overwinter in protected locations and become active when puncturevine seeds are developing.

Diet

feed on foliage and stems of Tribulus terrestris; larvae feed exclusively on developing seeds of this plant. Reproductive success depends on availability of green, developing seeds.

Host Associations

Tribulus terrestris - obligateStrong specificity; larvae develop only in seeds of this . may feed on foliage of related species but do not reproduce on them.

Life Cycle

Multiple per year; overwinters as in protected locations such as under bark or in plant litter. Larval development occurs entirely within puncturevine seeds. Oviposition into developing seeds; reproductive output tied to seed availability.

Behavior

seek out puncturevine plants for feeding and oviposition. Strong fidelity to plant; laboratory and field tests confirm larvae will not develop in seeds of non-host . Used in strategies, often in combination with M. lypriformis.

Ecological Role

herbivore and agent targeting an weed. Reduces puncturevine reproductive output through seed . Part of integrated weed management programs, though effectiveness varies with climate and plant .

Human Relevance

Intentionally introduced agent for puncturevine (Tribulus terrestris), a weed that injures livestock, reduces forage quality, and damages bicycle tires. Subject of research to improve efficacy in weed suppression.

Similar Taxa

Microlarinus lypriformisClosely related congeneric also used for puncturevine ; distinguished by stem-feeding larval versus seed-feeding in M. lareynii. The two species are often deployed together but require different monitoring approaches.

More Details

Biological Control History

Introduced to the United States in the early 1960s alongside M. lypriformis. Despite high reproductive potential, field success has been inconsistent due to mismatches between weevil climatic requirements and local conditions where puncturevine thrives.

Host Specificity Testing

Extensive laboratory and field testing has confirmed strong specificity to Tribulus terrestris, supporting its safety as a agent with minimal non-target risk.