General information

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Melissodes apicatus is geographically widespread, but little has been written about it; there is no published study of its nest biology.  This may be in part because it is a pollinator of pickerelweed (Pontederia cordata), a plant that is difficult to observe because it typically grows immersed in swamp water.  Thus, the Gainesville nest site offers a rare opportunity to document Melissodes apicatus behavior.

 

Original descriptions & associated flora.  Melissodes apicatus was first described in 1906 by J.H. Lovell and TDA Cockerell, who based their observations on a single female found feeding on Pontederia cordata in Maine (Lovell & Cockerell 1906).  In 1956, calling it "a rare and poorly known species," LaBerge described the male and redescribed the female. 

 

LaBerge  (1963) affirmed that Melissodes apicatus was found primarily on Pontederia, but he reported records of M. apicatus  visiting other flowers, probably for nectar: these included female bees in Florida visiting Cirsium; and male bees in Florida found on Melilotus albus, Oenothera speciosa and Stachys floridana.  

 

Range:  LaBerge (1956, 1963) reported that the species’ distribution extended along the Atlantic Coast from Maine to Florida. Nearly 25 years later, Bouseman (1987) wrote that that as of 1987, Melissodes apicatus had been recorded  “from every state east of the Mississippi River except West Virginia, from Minnesota to Texas west of the river and from adjacent southern Canada.”  He also noted that there had been no studies of the bee since LaBerge, although there were anecdotal reports suggesting that Melissodes apicatus needed sandy environments for nesting.

 

The nesting habits of the 2024-2025 Melissodes apicatus found in Gainesville shed some light on why so little is known about these species:  the females build nests without entrances, so that their nests are very hard to find.  It is possible to be standing on top of a large Melissodes apicatus aggregation without even knowing that it is there.

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Some traits of female Melissodes apicatus:

 

Female Melissodes apicatus found in 2024 and 2045 at the nest site are typically 11-12 mm in size.  Notable traits of females include: 

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(1) CLYPEUS:  The clypeus is protuberant.  Both the clypeus and labrum are coarsely pitted, and long brown hairs cover the labrum.  

 

(2)  THORAX:  The hair on the scutum and scutellum is dark, with an outline of long white hairs. The hair on the mesepisternum is entirely pale.  When female Melissodes apicatus are viewed from a distance, the combination of white and dark hairs gives them an overall grayish appearance.

 

(3) PRONOTAL LOBES:  There are small patches of dark hairs partially covering the pronotal lobes; this trait helps distinguish this species from other Florida  Apomelissodes such as M. mitchelli

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(4) TERGAL BANDS:  The pale tergal hair bands on T2-T4 are  situated along the hind (apical) rim of each segment.  The pale apical band on T3 is entire (uninterrupted).  On T2, the band is nearly entire.  

 

(5) AN ADDITIONAL NOTE ABOUT TERGAL BANDS:
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Mitchell (1963) described the pale apical band of T2 as "more or less interrupted" on Melissodes apicatus.  I have observed, however, that on fresher specimens, T2 is usually entire, although it tends to narrow medially.

 

I might add that T2 is vulnerable to wear and tear because it is only partially covered by the wings, and thus exposed to frequent contact with abrasive sandy soils whenever females "swim" through the ground to their nest tunnels.   

 

By contrast, on M. mitchelli, T2 is fairly widely interrupted, and T3 is also interrupted.  This character allows for easy differentiation between these two species in the field.  The dark hairs over the pronotal lobes, which (along with the bees' specialist plant associations) best distinguish the species, are not visible to the naked eye and are often obscured by surrounding lighter hairs.