Pachodynerus

Saussure, 1875

potter wasps

Pachodynerus is a of approximately 50 of solitary in the Eumeninae. The genus exhibits highest diversity in central South America, with species distributed across the Neotropical and Nearctic regions. These are cavity-nesters that construct mud in pre-existing holes, including abandoned burrows, stems, and human-made structures. Several species have been beyond their ranges, including P. nasidens which has established on oceanic islands and caused aviation safety incidents in Australia by nesting in aircraft pitot .

Pachodynerus by (c) Luiz Puodzius, some rights reserved (CC BY), uploaded by Luiz Puodzius. Used under a CC-BY license.

Pachodynerus erynnis by (c) Richard Stovall, some rights reserved (CC BY), uploaded by Richard Stovall. Used under a CC-BY license.

Red-marked Pachodynerus - Pachodynerus erynnis, Key Deer National Refuge, Summerland Key, Florida, January 30, 2022 (52264129164) by Judy Gallagher. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Pachodynerus: //ˌpækoʊˈdaɪnərəs//

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Identification

Pachodynerus can be distinguished from the closely related Euodynerus by subtle morphological differences. Pachodynerus nasidens has and black coloration essentially identical to the Mexican (Brachygastra mellifica), serving as a convincing mimic. P. guadulpensis (formerly P. praecox) is distinguished from P. nasidens by an extra yellow stripe across the of the . Species-level identification typically requires examination of collected specimens.

Images

Habitat

Grassland areas, Araucaria forest, and swamp areas. occupy diverse including wet cool temperate zones with hoar frosts, heterogeneous sites with mixed forests and grasslands, and tropical regions. Nesting occurs in pre-existing cavities including hollow twigs, borings in dead standing trees, vacated , abandoned mud dauber nests, nests, and human-made structures such as wooden posts with holes, electrical sockets, and keyholes.

Distribution

Neotropical and Nearctic regions with highest diversity in central South America. range extends from southern United States (Arizona, Texas, Florida) through Mexico and Central America to South America. P. nasidens to Hawaii, Micronesia, several Atlantic and Pacific islands, and Australia (arrived 2010). P. erynnis occurs on Ascension Island and in North America. recorded from Brazil (Paraná), Jamaica, and throughout the continent.

Seasonality

Nesting activity varies by and region. In southern Brazil: P. guadulpensis, Pachodynerus sp., and P. argentinus nest from December to March (P. guadulpensis with one October nest); P. ca guadulpensis in March; P. nasidens from January to April. In Australia, peak nesting occurs in summer months (November–March), with nesting success optimal between 24–31°C.

Life Cycle

Solitary. Females construct linear series of cylindrical mud forming continuous tubes, with cell partitions of mud thick at extremities and thinner at middle. Closure plug consists of thick mud layer. attached to upper of cell by thin short peduncle. develop within silvery adhered to cell walls. Development includes during winter (295 days observed in P. guadulpensis). Proterandry observed: innermost cells contain females, outermost cells males. Female immatures larger, take more time to develop, and receive more provisions than males.

Behavior

Females are solitary and seek natural cavities for nesting. They inspect, clean, and accept nest sites before provisioning. () are paralyzed with and stuffed into galleries; are laid within the chamber, which is sealed with mud. Females demonstrate control, placing male eggs near openings and female eggs deeper in galleries to prevent conflicts. Some show plasticity in nesting , utilizing abandoned burrows, excavated soil nests, or mud constructions attached to plants or rocks.

Ecological Role

Predatory that function as agents of pests. P. erynnis specifically preys upon (Spodoptera spp.), (Agrotis spp.), and (), and has been associated with increased pest control in managed landscapes. provide services while foraging for nectar and pollen.

Human Relevance

Highly for of agricultural and landscape pests. P. nasidens has become an of concern: in Australia, nesting in aircraft pitot caused serious aviation safety incidents by obstructing airspeed measurements. Management strategies include modification near airports, provision of alternative nest sites, covering pitots between , and regular . Can be encouraged in gardens by providing trap-nests (wooden blocks with drilled holes 0.7 cm diameter, 77–124 mm depth) and flowering plants such as mountain mint (Pycnanthemum) and spotted horsemint (Monarda).

Similar Taxa

EuodynerusMost closely related ; Pachodynerus distinguished by subtle morphological characters
Brachygastra mellifica (Mexican honey wasp)P. nasidens is a convincing mimic with essentially identical and black markings; distinguished by solitary vs. social and different nesting habits
TrypoxylonAlso called 'keyhole ' and nest in pre-existing cavities; distinguished by long slender , single submarginal in , and
Monobia quadridens (four-toothed mason wasp)Related eumenine with similar cavity-nesting and ; occurs in eastern North America including DMV region

More Details

Nest Architecture

Nests comprise linear series of cylindrical fitting perfectly into continuous tubes. Cell partitions are thick at extremities and thinner at middle. Vestibular cells are common, especially in P. nasidens where they occupy almost all trap length. Intercalary cells present in some nests. All studied Brazilian used only 0.7 cm diameter trap-nests.

Sex Allocation and Parental Investment

Sex ratio varies with trap length: female-biased in short traps, approximately unity in longer traps. Female have slightly higher volume than male cells. The greater cost to produce females (larger size, longer development, more provisions) leads to strategic sex placement by females.

Natural Enemies

Nests are besieged by diverse enemies including (Chrysis), parasitic (Melittobia chalybii, ), satellite (Amobia floridensis), acrobat (Crematogaster), (Macrosaigon, Ripiphoridae), and (Pseudoxenos).