Argidae

Argid Sawflies

Genus Guides

is a large of (Hymenoptera: ) comprising approximately 800 worldwide, with greatest diversity in tropical regions, particularly the Neotropics. The family is distinguished from other Symphyta by the reduction of the to three flagellomeres, with the terminal segment often elongated and forked in males. Larvae are phytophagous and frequently exhibit gregarious feeding ; some species display maternal care of and young larvae.

Arge scapularis by (c) Lacy L. Hyche, Auburn University, some rights reserved (CC BY). Used under a CC-BY license.

Atomacera decepta by (c) Bill Keim, some rights reserved (CC BY). Used under a CC-BY license.

Schizocerella lineata by (c) Mark Richman, some rights reserved (CC BY), uploaded by Mark Richman. Used under a CC-BY license.

Pronunciation

How to pronounce Argidae: /ˈɑr.dʒɪ.daɪ.iː/

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

Identification

The three-segmented immediately separate from all other . Male specimens can often be recognized by the distinctive forked or elongated terminal antennal segment. Within the family, Arginae and Sterictiphorinae are recognized, with Arginae containing generally larger often associated with flowers.

Images

Appearance

are distinguished from all other by reduced to three segments (flagellomeres). The terminal flagellomere is often elongated and shaped like a tuning fork in males of many . Body size varies considerably, with larger species in the Arginae. Coloration ranges from cryptic to conspicuously aposematic in some groups.

Habitat

of larger Arginae are frequently found on flowers. Larvae occur on plant foliage where females deposit , often in groups on leaf surfaces. Some species are associated with specific host plants including seagrape (Coccoloba uvifera), purslane (Portulaca oleracea), and various trees.

Distribution

distribution across tropical, temperate, and subarctic regions. Highest diversity occurs in the Neotropical region (over 350 , 32 ) and sub-Saharan Africa. The exhibits Gondwanan biogeographic patterns with Australian and Neotropical regions representing ancestral distributions for major .

Diet

Larvae are phytophagous, feeding on plant foliage. Some are internal leaf miners (e.g., Schizocerella pilicornis in purslane leaves), while most feed externally. A few species attain pest status, including Aproceros leucopoda on elms and of Sericoceros species on seagrape.

Host Associations

Coccoloba uvifera - seagrape; primary for Sericoceros krugii
Portulaca oleracea - purslane; for Schizocerella pilicornis (internal )
Ulmus spp. - elms; for pest Aproceros leucopoda
Pyracantha fortuneana - for Arge pyracanthae
Manglietia conifera - Mo tree; subject of recent by Shizocera sp. in Vietnam

Life Cycle

Females deposit in groups on leaf surfaces using a saw-like ovipositor. Larvae typically feed for several days through multiple instars. Many exhibit gregarious larval feeding with defined feeding patterns. occurs in soil or on bark, often in silken cocoons; some species weave group cocoons protected by a common cover. Multiple per year occur in warmer climates (up to 6-7 generations reported for Schizocerella pilicornis in Illinois).

Behavior

Several exhibit maternal care, with females guarding masses and young larvae. This has evolved independently in and Pergidae, with a single origin in the Dielocerini tribe of Sterictiphorinae. Larvae of many species feed gregariously, and some display aposematic coloration associated with chemical defenses. When disturbed, some larvae coil and may release defensive volatile compounds.

Ecological Role

Larvae function as herbivores, occasionally reaching pest densities. Some provide minor of weeds (e.g., Schizocerella pilicornis on purslane). larvae serve as prey for various including tachinid flies and ichneumonid wasps.

Human Relevance

Most are economically insignificant. Aproceros leucopoda (zigzag elm sawfly) is an pest in Europe and North America, causing repeated defoliation of elm trees. Sericoceros krugii periodically on seagrape in Puerto Rico. Schizocerella pilicornis has been investigated as a agent for common purslane.

Similar Taxa

TenthredinidaeOther major ; distinguished by with 6 or more segments (vs. 3 in )
PergidaeAnother with some maternal care ; distinguished by morphological characters including wing venation and larval

More Details

Taxonomic Diversity

The Neotropical fauna includes more than twice the number of (32) and nearly half the of all other regions combined. The Arginae and Sterictiphorinae represent the two major lineages within the .

Chemical Defenses

Larvae of many produce potent defensive chemicals de novo, which has influenced the evolutionary relationship between larval appearance and gregariousness. Warning coloration appears more effective against vertebrate than .

Evolutionary History

Divergence of -Pergidae and Arginae-Sterictiphorinae is estimated to have occurred in the middle-upper Jurassic, associated with the breakup of Gondwana. Diversification may be linked to angiosperm radiation in the Early Cretaceous.