near an active nest entrance to protect the colony and seek mating opportunities. For males that are near the nest entrance, their boundaries are usually linear and several meters long. For males that are farther from the exit, their boundaries are usually in the shape of a square and shorter in length. Males can stay in one territory for as long as two weeks. Although they do most of their foraging and resting during the night, they take small breaks throughout the day as well. After these breaks, they often have to fight off intruders that have taken advantage of their absence. Flights near the nest are usually uniform and involve much hovering. Flights protecting a bee's territory can be as short as a few minutes, but may extend beyond an hour. Males will not react to another bee unless the other is flying at high speed. When other individuals hover near the nest, it is unlikely that the male will pursue, whereas if another male comes into a territory at a high speed, the territorial male will give chase. When males patrolling the entrance of a nest are confronted with either dead or living Eastern carpenter bees suspended from a thread and dangled within the male's territory, the male does not respond when the bee is suspended and motionless, whether it is living or dead—even though X. virginica are capable of recognizing other individuals of their species. However, when the suspended bee is released and allowed to fly in the male's territory or is swung through the territory on the thread, the territorial male pursues it. Parasites There is one common species of bombyliid flies known to parasitize the larvae of Xylocopa virginica: Xenox tigrinus. Marking Eastern carpenter bees have mandibular glands that are known to produce a marking chemical in X. hirsutissima that functions as a nest marker or for female attraction. The glands are present in both males and females, but they produce no marking substance. However, X. virginica does have a Dufour's gland that is used to deposit a scent on a flower immediately following nectar collection. The scent, composed of hydrocarbons and esters, discourages X. virginica, as well as other bee species, from returning to that same flower. Stinging The male bee is unable to sting because the stinger is simply a modified ovipositor (which males lack by definition), though they will commonly approach human