Pergidae

pergid sawflies

Genus Guides

1

is the third-largest of (Hymenoptera: ), with approximately 450 described . The family is distributed primarily in the Australasian and Neotropical regions, with South America and Australia representing the greatest diversity. Members exhibit considerable morphological variation in structure, ranging from simple to pectinate or bipectinate forms, and frequently display . Several species are economically significant as agricultural pests or livestock toxins, while others have been evaluated as agents.

Acordulecera by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.Acordulecera dorsalis by (c) Joseph McPhail, some rights reserved (CC BY), uploaded by Joseph McPhail. Used under a CC-BY license.Acordulecera by (c) Cecil Smith, some rights reserved (CC BY), uploaded by Cecil Smith. Used under a CC-BY license.

Pronunciation

How to pronounce Pergidae: //ˈpɜːrɡɪdiː//

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

Identification

vary considerably in segment number and form, from simple to serrate, pectinate, or bipectinate. is common, with differences in antennae type, coloration, and size between sexes. Some are ( Cladomacra in Papua New Guinea and Indonesia) or have brachypterous females (Clarissa tasbates in Tasmania).

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Habitat

Diverse across Australasian and Neotropical regions. Many Australian associated with Eucalyptus forests. Some Euryinae are ground-dwelling, saprophagous, and or . Larvae of some species occur in pastures and grazing lands.

Distribution

Western Hemisphere from southeastern Canada through eastern United States to southern Chile, with greatest diversity in the Neotropics. Australasian Region including Australia (including Tasmania), New Guinea, New Britain, Sulawesi, and Indonesia. One introduced (Phylacteophaga froggatti) in New Zealand and New Caledonia.

Seasonality

activity and larval occurrence vary by region and . Tequus schrottkyi has several between March and July in Uruguay. Perreyia flavipes larvae appear between June and September in southern Brazil. Phylacteophaga froggatti discovered in New Zealand in March 1985.

Diet

Extremely diverse food plants. Many Australian feed on Eucalyptus species. Other food plants include dead or dying leaves, aquatic ferns, fungi, Solanum species, Nothofagus, Psidium (guava), oaks, hickories, Melaleuca quinquenervia, and Schinus terebinthifolius. Some Euryinae are saprophagous. Most are external leaf feeders; some are shoot borers or leaf miners.

Life Cycle

Complete : , larva (several instars), pupa, and . Phylacteophaga froggatti has four feeding instars in males and five in females, followed by a non-feeding . Tequus schrottkyi larvae spin silk cocoons in soil for . Eggs laid individually in leaf margins into leaf tissue in some .

Behavior

Gregarious common in larvae. Larvae of Perreyia travel in groups on the ground, forming tight-knit masses crawling over each other, and locate group sites. Perga larvae exhibit periodic halts with abdominal raising and lowering to communicate movement initiation within groups. Perga dorsalis larvae show situational leadership in collective foraging. Lophyrotoma larvae cut leaf midveins before feeding, with some species severing petioles when leaving. Some Australian species in Perginae, Philomastiginae, and South American Syzygoniinae exhibit maternal care.

Ecological Role

Herbivores contributing to leaf damage and nutrient cycling. Some sequester plant defensive compounds, rendering larvae unpalatable to . Potential agents for weeds including Melaleuca quinquenervia and Schinus terebinthifolius. include Braconidae and Eulophidae.

Human Relevance

Agricultural pests: of Tequus on potatoes in Peru and Bolivia; Cerospastus volupis defoliates Nothofagus in Chile and Argentina; numerous species damage Eucalyptus in Australia; Phylacteophaga leafminers introduced to New Zealand and New Caledonia; Haplostegus, Enjijus, and Sutwanus on guava in Central and South America; Acordulecera on oaks and hickories in eastern North America. Livestock : larvae of Perreyia flavipes and related species cause acute hepatic and death in sheep, goats, and pigs when ingested, with substantial financial losses in Brazil, Uruguay, and Australia. potential: Lophyrotoma zonalis evaluated for Melaleuca quinquenervia control in Florida; Heteroperreyia hubrichi for Brazilian peppertree control.

Similar Taxa

  • TenthredinidaeLargest ; distinguished from by generally simpler without the extreme variation in segment number and pectinate forms found in Pergidae
  • ArgidaeSecond-largest ; Argidae larvae often display alternate appearances between instars, whereas typically maintain consistent larval coloration; both families produce defensive but differ in evolutionary patterns of gregariousness and conspicuousness

More Details

Defensive chemistry

Larvae of Argidae and produce potent defensive chemicals de novo, including toxic . This chemical defense has influenced evolutionary relationships between larval appearance and gregariousness, with most Pergidae being conspicuous-gregarious. Perreyia flavipes larvae contain D--containing peptides responsible for livestock toxicosis.

Feeding adaptations

Some Eremophila-visiting have maxillary palpi modified into a tube for nectar-feeding, analogous to the tube formed by enlarged maxillary palpi in some Australian Colletidae bees. Perga affinis affinis larvae store at least 80% of ingested sideroxylonal-A in the , with less than 1% excreted, without apparent feeding inhibition.

Fossil record

Baladi warru, a Miocene fossil from McGraths Flat, New South Wales, represents the first Australian pergid fossil and belongs to Perginae. Ancestral character reconstruction indicates four independent adaptations to toxic Myrtaceae as plants.

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