# Colletes validus

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Colletes_validus
> Markdown URL: https://mediated.wiki/source/Colletes_validus.md
> Source: https://en.wikipedia.org/wiki/Colletes_validus
> Source revision: 1193966316
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Species of bee

Colletes validus Scientific classification Kingdom: Animalia Phylum: Arthropoda Clade: Pancrustacea Class: Insecta Order: Hymenoptera Family: Colletidae Genus: Colletes Species: C. validus Binomial name Colletes validus Cresson, 1868

***Colletes validus***, colloquially known as the **blueberry cellophane bee**, is a solitary, specialist bee in the family [Colletidae](/source/Colletidae). It is found primarily in eastern North America where it nests in sandy soils near [ericaceous](/source/Ericaceae) plants.[1]

## Description

Colletes validus face. Note the long, triangular impression. This shape give Colletes validus easy access to deep ericaceous flowers.

*C. validus* is a medium-sized cellophane bee: females are 13–14 mm (0.51–0.55 in) long and males are 10–12 mm (0.39–0.47 in) long.[2] As is the case with members of the genus *[Colletes](/source/Colletes),* all individuals have an S-shaped 2nd recurrent vein on the forewing. Most notably, *C. validus* males and females have an exaggerated malar space, giving the impression of a long, triangular face.[2] These two characteristics are diagnostic for *C. validus* within its range.[2] Males are covered densely with brown-yellowish hairs, giving fresh individuals a golden tinge. Females are less hairy and have reduced, but present [scopa](/source/Scopa_(biology)) on the hind legs. It is similar to *C. inaequalis* Say and *C. thoracicus* Smith in appearance, range and phenology, however both of these species lack the distinctive long face.[1]

## Distribution

Its range extends from the Mid-Atlantic states north through New Hampshire and west through Michigan, with sparse records west to Wisconsin and north to Ontario.[2] *C. validus* is found throughout this range in sandy areas in proximity to [ericaceous](/source/Ericaceae) plants.[1] Records from Georgia and Florida likely belong to a newly described species, *C. ultravalidus.*[3]

## Phenology

*C. validus* is a univoltine bee that flies in early spring, coinciding with the flowering of *[Vaccinium](/source/Vaccinium)* and other [ericaceous](/source/Ericaceae) plants.[1] Near the southern extent of its range, adults fly in late-March, whereas further north flight occurs three to four weeks later. Males emerge precociously, i.e. a few days before females, and patrol nesting aggregations for mates.[1] They locate females via pheromones and mate at the nest site. Females commence nest excavation upon emergence and can use their emergence burrow as the start of their nest. A high degree of [natal philopatry](/source/Natal_philopatry), i.e. nesting in your birthplace, is not uncommon for aggregating bees like *C. validus*. If females emerge too early and their pollen hosts have not started flowering, they can wait for the flowering to begin by sitting in their nest entrance and nectaring on available flowers of other plants.[4] Males disappear from the aggregation two to three weeks after emergence, leaving females as the only flying *C. validus* at the end of the season.

Nesting proceeds between four and six weeks, with each nest taking between five and ten days to complete.[1] Nests develop underground through the end of summer: eggs hatch into larvae, larvae grow on the semi-liquid provisions provided by the parent bee, and larvae pupate into adults. Anecdotal evidence from nests excavated early March[1] suggests that some prepupae (fully developed larvae) enter diapause before pupating. Whether these prepupa ever complete development is unknown as are the factors driving diapause initiation.

## Nesting Habitat

A sandy slope on which Colletes validus typically nests. Photo taken in Concord, NH.

*C. validus* is a gregarious nester, meaning that nests often occur in aggregations (≈5 nests/m2 ).[4] Nesting sites are located in open sandy soils with sparse vegetation, often located close to their ericaceous hosts. Nests can be found on flat ground or south-facing slopes, but rarely under a closed canopy since *C. validus* prefers warm soils. Dense grass deters nesting.[1]

Surprisingly, *C. validus* is completely absent from surveys in the [lowbush blueberry](/source/Vaccinium_angustifolium) fields of Maine despite the tremendous abundance of host plant and presence of its generalist congener, *C. inaequalis*.[5] One explanation is that cold springtime soils discourage nesting, but this hypothesis has not been rigorously tested. Clearly, there are other factors besides open, sandy soil and host plant presence determining the nesting of *C. validus* within its range.

## Host Plant and Foraging

The common name of *C. validus*—blueberry cellophane bee—suggests a tighter relationship with its host plant than may actually exist. Evidence suggests it is not limited to blueberry (*Vaccinium* spp*.*) and it will forage for pollen broadly on a diversity of ericaceous plants with [urceolate](/source/Urceolate) flowers, e.g. [bearberry](/source/Bearberry) (*Arctostaphylos uva-ursi)* and [black huckleberry](/source/Black_huckleberry) (*Gaylussacia baccata*).[1] Pollen provisions can contain up to 15% *[Pinus](/source/Pinus_rigida) spp.* pollen and males and females have been observed visiting non-ericaceous plants (e.g. *[Acer rubrum](/source/Acer_rubrum), [Prunus](/source/Prunus)* spp.*, [Amelanchier](/source/Amelanchier)* spp.) for both pollen and nectar.[1] Part of the provisions are held within the crop during foraging and regurgitated upon return to the nest.

## Nesting Biology

Blueberry cellophane bee (Colletes validus) female excavates a nest near host blueberry plants in Falmouth, MA.

Nests descend from 17 to 60 cm (6.7 to 23.6 in) and measure ≈8 mm (0.31 in) in diameter.[4] Tunnel walls are not compacted since *C. validus* lacks a pygidial plate normally used for tamping down soil (a trait shared by all *Colletes*).[1] Cells are constructed at the end of short lateral tunnels arranged radially around the main tunnel. Laterals are constructed from the bottom to the top.[4] She proceeds by “painting” a [Dufour's gland](/source/Dufour's_gland) secretion mixed with saliva onto the walls of the cell using her short, bilobed glossa.[6] This mixture polymerizes into a polyester- or cellophane-like substance, which is where bees in the genus *Colletes* get their common name.[6] Cell construction primarily occurs at night and provisioning of the cell follows the next morning.[1] To provision the cell, the female first forages for ericaceous pollen and packs it into the bottom third of the cell.[4] Next, she adds nectar until a viscous soup is formed.[4] The waterproof cellophane lining of the cell permits the usage of semi-liquid provisions. Bacteria (*Lactobacillus* spp.*)* and/or yeast likely colonize the provisions based on visible gas bubbles and sour taste (pH 3–4).[1] Fermentation is common in other colletids that create liquid provisions, e.g. *[Ptiloglossa](/source/Ptiloglossa) guinnae*.[7] The female hangs a single egg (≈2.65mm in length) from the top of the cell so that the egg is not submerged in the provisions.[4] A maximum of five cells have been associated with any given nest.[1][4] It is unknown whether females create more than one nest during their lifetime.

## Natural Enemies

Blister beetles ([Tricrania sanguinipennis](/source/Tricrania_sanguinipennis)) parasitize Colletes validus nests. Adult beetles lay eggs in sand that hatch into triungulin larvae. Larvae actively seek out adult bees in order to be transported down into the bee nest.

A variety of arthropods prey on *C. validus* nests. Adults of the blister beetle *[Tricrania sanguinipennis](/source/Tricrania_sanguinipennis)* (Coleoptera) have been found in completed *C. validus* cells.[1] [Bee flies](/source/Bombyliidae) (*Bombylius mexicanus, B. pygmaeus* in Beltsville, MD) have been observed ovipositing in the nest entrances of *Colletes validus*, but no larvae have been recovered from cells.[1] [Robber flies](/source/Asilidae) (*Nicocles pictus*) predate adult *C. validus (*Batra 1980).[1] There are no known hymenopteran [cleptoparasites](/source/Kleptoparasitism) of *C. validus*.

## Pheromones

Entomologists have long-noted the citrus-like odor emitted by *Colletes* when handled.[4] Female *C. validus* will swarm around netted females emitting this odor. Past research has found that *C. validus* will aggregate around 1-terpinen-4-ol[4] and a 3:1:1: mixture of [linalool](/source/Linalool)-neral-geranial.[1] The exact aromatic profile of the *Colletes* attractant pheromone is unclear but could prove valuable for attracting *C. validus* to nesting sites for commercial pollination efforts.

## Relationship to humans

*C. validus* can nest on footpaths through sand plain preserves or in open backyards built on sandy [oak-pine forests](/source/Pine_barrens) (e.g. [Barnstable County, Massachusetts](/source/Cape_Cod)), resulting in possible conflict with humans and pets. However, concern is unwarranted as *C. validus* is docile and will not sting unprovoked. Like many other bees, they will forage for salts from human sweat on hot days.

## Crop Pollination

The potential of *C. validus* as a commercial blueberry pollinator has been acknowledged, but never fully explored.[4] *C. validus* has many of the characteristics of a bee that could be commercially managed for pollination including a preference for blueberry flowers, a phenology that almost exclusively overlaps with the bloom time of blueberry, and an ability to extract pollen from the deep, goblet flowers.[4] Understanding how to attract wild *C. validus* to nesting aggregations and initiate nesting would be a useful first step towards securing reliable pollination on farms.

## Further reading

- Ascher, J.S.; Pickering, J. (2019). ["Discover Life bee species guide and world checklist (Hymenoptera: Apoidea: Anthophila)"](https://www.discoverlife.org/mp/20q?search=Apidae). Retrieved 2019-07-02.

## References

1. ^ [***a***](#cite_ref-Batra_1980_1-0) [***b***](#cite_ref-Batra_1980_1-1) [***c***](#cite_ref-Batra_1980_1-2) [***d***](#cite_ref-Batra_1980_1-3) [***e***](#cite_ref-Batra_1980_1-4) [***f***](#cite_ref-Batra_1980_1-5) [***g***](#cite_ref-Batra_1980_1-6) [***h***](#cite_ref-Batra_1980_1-7) [***i***](#cite_ref-Batra_1980_1-8) [***j***](#cite_ref-Batra_1980_1-9) [***k***](#cite_ref-Batra_1980_1-10) [***l***](#cite_ref-Batra_1980_1-11) [***m***](#cite_ref-Batra_1980_1-12) [***n***](#cite_ref-Batra_1980_1-13) [***o***](#cite_ref-Batra_1980_1-14) [***p***](#cite_ref-Batra_1980_1-15) [***q***](#cite_ref-Batra_1980_1-16) [***r***](#cite_ref-Batra_1980_1-17) Batra, S. W. T. (1980). "Ecology, Behavior, Pheromones, Parasites and Management of the Sympatric Vernal Bees Colletes inaequalis, C. thoracicus and C. validus". *Journal of the Kansas Entomological Society*. **53** (3): 509–538. [JSTOR](/source/JSTOR_(identifier)) [25084067](https://www.jstor.org/stable/25084067).

1. ^ [***a***](#cite_ref-Mitchell_2-0) [***b***](#cite_ref-Mitchell_2-1) [***c***](#cite_ref-Mitchell_2-2) [***d***](#cite_ref-Mitchell_2-3) Mitchell, TB. "Bees of the Eastern United States". *North Carolina Agricultural Experiment Station Technical Bulletin*. **1**: 23–85.

1. **[^](#cite_ref-3)** Hall, H. Glenn; Almquist, David T.; Ascher, John S. (2016-01-29). ["A new species of Colletes (Hymenoptera: Apoidea: Colletidae) from northern Florida and Georgia, with notes on the Colletes of those states"](https://journals.ku.edu/melittology/article/view/4993). *Journal of Melittology* (58): 1–20. [doi](/source/Doi_(identifier)):[10.17161/jom.v0i58.4993](https://doi.org/10.17161%2Fjom.v0i58.4993). [ISSN](/source/ISSN_(identifier)) [2325-4467](https://search.worldcat.org/issn/2325-4467).

1. ^ [***a***](#cite_ref-Rajotte_1979_4-0) [***b***](#cite_ref-Rajotte_1979_4-1) [***c***](#cite_ref-Rajotte_1979_4-2) [***d***](#cite_ref-Rajotte_1979_4-3) [***e***](#cite_ref-Rajotte_1979_4-4) [***f***](#cite_ref-Rajotte_1979_4-5) [***g***](#cite_ref-Rajotte_1979_4-6) [***h***](#cite_ref-Rajotte_1979_4-7) [***i***](#cite_ref-Rajotte_1979_4-8) [***j***](#cite_ref-Rajotte_1979_4-9) [***k***](#cite_ref-Rajotte_1979_4-10) [***l***](#cite_ref-Rajotte_1979_4-11) Rajotte, Edwin G. (1979). "Nesting, Foraging and Pheromone Response of the Bee Colletes validus Cresson and Its Association with Lowbush Blueberries. (Hymenoptera: Colletidae) (Ericaceae: Vaccinium)". *Journal of the Kansas Entomological Society*. **52** (2): 349–361. [JSTOR](/source/JSTOR_(identifier)) [25083914](https://www.jstor.org/stable/25083914).

1. **[^](#cite_ref-5)** Bushmann, Sara L.; Drummond, Francis A. (August 2015). "Abundance and Diversity of Wild Bees (Hymenoptera: Apoidea) Found in Lowbush Blueberry Growing Regions of Downeast Maine". *Environmental Entomology*. **44** (4): 975–989. [doi](/source/Doi_(identifier)):[10.1093/ee/nvv082](https://doi.org/10.1093%2Fee%2Fnvv082). [ISSN](/source/ISSN_(identifier)) [1938-2936](https://search.worldcat.org/issn/1938-2936). [PMID](/source/PMID_(identifier)) [26314043](https://pubmed.ncbi.nlm.nih.gov/26314043).

1. ^ [***a***](#cite_ref-Almeida_2008_6-0) [***b***](#cite_ref-Almeida_2008_6-1) Almeida, Eduardo A.B. (January 2008). ["Colletidae nesting biology (Hymenoptera: Apoidea)"](https://www.apidologie.org/articles/apido/abs/2008/01/m07113/m07113.html). *Apidologie*. **39** (1): 16–29. [doi](/source/Doi_(identifier)):[10.1051/apido:2007049](https://doi.org/10.1051%2Fapido%3A2007049). [ISSN](/source/ISSN_(identifier)) [0044-8435](https://search.worldcat.org/issn/0044-8435).

1. **[^](#cite_ref-7)** Roberts, Radclyffe B. (1971). "Biology of the Crepuscular Bee Ptiloglossa guinnae N. Sp. with Notes on Associated Bees, Mites, and Yeasts". *Journal of the Kansas Entomological Society*. **44** (3): 283–294. [JSTOR](/source/JSTOR_(identifier)) [25082419](https://www.jstor.org/stable/25082419).

## External links

- Media related to [Colletes validus](https://commons.wikimedia.org/wiki/Category:Colletes_validus) at Wikimedia Commons

Taxon identifiers Colletes validus Wikidata: Q2102631 Wikispecies: Colletes validus BOLD: 162340 BugGuide: 511313 CoL: X3MD EoL: 1047509 GBIF: 1348922 iNaturalist: 199055 IRMNG: 11357884 ITIS: 655064 NatureServe: 2.882072 Observation.org: 170088 Open Tree of Life: 3275010

---
Adapted from the Wikipedia article [Colletes validus](https://en.wikipedia.org/wiki/Colletes_validus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Colletes_validus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.