Dear Bee Netters
 
My PhD project will be looking at possible resource competition between
honeybees and native Hylaeus bees. It is similar in design to Michael
Schwarz and team' s project on resource competition between feral honeybees
and native Exoneura bees. I will run an experiment examining the impact of
feral honeybees by setting up a number of control and experimental sites.
Each site will contain 60- 80 Hylaeus nests (stems of fronds of the tree-
fern - Cyathea australis). Since it is impossible to establish control
sites that have no feral honeybees because of their widespread occurrence
throughout most forests, the effect of honeybees will be assessed by
slightly increasing the presence of honeybees in experimental sites. That
is, by placing 6 honeybee hives at each of these sites. The following data
will be collected from control and experimental nests at the termination of
the experiments, and at approximately, every four weeks throughout the
experiments using supplemental nests: the number and species of each adult
bee, number and developmental stages (that is, eggs, larval stage, prepupae
and pupae) of immature brood, total dry weight of brood; sex of mature
brood and number, nest lengths, species of other nest occupants (for
example, predators and parasitoids) and duration of nest occupation.
Destructive samples of pollen will also be taken from brood cells within
nests. Floral density and phenology will be assessed by conducting two 50m
vegetation transects at each site every 2- 3 weeks throughout the Spring
and Summer and every four weeks at other times. A pollen library will be
constructed from pollen samples taken from nests to help keep track of
resource utilization throughout the season. Hylaeus adults have the
convenient habit of sealing brood and pollen supplies in a linear series of
cells along the length of a nest. This sequential construction of cells
allows the gathering of data relating to pollen usage as well as, immature
development, rates of provisioning and brood success throughout the season.
 
If I'm lucky, I may also be able to conduct a 'control- experimental site'
experiment to examine resource competition due to typical bee- keeping
practices. This is also being investigated by Schwarz et al.  However, I
will only be able to do this if and when 'honey- bee' conditions in forests
that are accessible to me, occur;  and if I can gain collaboration from the
Victorian Apriarists Association.
 
There are a number of differences between Hylaeus and Exonuera- the subject
of Schwarz et. al' s project. Comparitively nothing is known about Hylaeus
biology including its sociality. Apparently they' re solitary.....but
wethinks they may not. Does anyone have any information in this regard?
Solitary bees may be more vulnerable to competitive pressures because
decreased foraging efficiency by the adult may result in either her death
which will invariably spell the end for her brood or more likely, longer
foraging trips which will place the nest at greater risk from predators and
parasitoids. Due to their short- tongues, Hylaeines (and the Colletines and
Euroglossines for that matter) are largely restricted to the shallow-cupped
flowers of the Myrtacae, which could well explain their predominance in the
Australian bee fauna. (BTW. Didn't Michener (1965) rate the Australian bee
fauna as the most distinctive in the world, primarily because most of the
genera and over half of the named species of bees belong to the family
Colletidae). Anyway, this degree of oligolecty could be a problem as
Eucalypts are known to be intensively worked by commercial and feral
honeybees during honey- flow conditions. Unfortunately, I doubt very much
that I will get a handle on the foraging behaviour of Hylaeus. Eucalypts
have a tendency to be slightly taller than most net- wielding
entomologists. Measuring trip durations to the nest may however, yield some
indirect data on foraging behaviour. Would anyone like to comment on pollen
utilization, pollinating behaviour or foraging beaviour by Hylaeus ? or
Colletids in general ? Do Hylaeus actually transfer pollen even though they
do not possess scopae?
 
I am open to any suggestions regarding the project and Hylaeus (or
Colletids, generally). I would also be interested in obtaining references
to recent theoretical work (including math. modelling) on species invasions
of native communities, competition and tri- trophic interactions
(specifically host- pollinator- predator interactions).
 
Thanks
 
 
Allan C. Spessa