A lot of people have asked me about the interaction between native bees and honeybees: do they compete? do they avoid each other? do they disturb each other when foraging? It turns out a lot of ecologists and biologists have had those same questions, so there’s been a large amount of research done on the topic. Unfortunately, results vary with species and studies.
So, to briefly answer your questions, I’ve decided to 1) summarize the information available about honeybee-native bee interactions, and 2) provide you with a list of papers you can read if you want to learn more.
On Melastoma affine flowers: Gross and Mackay (1998) found that honeybees negatively affect native bee fitness. According to the authors, native bees in Australia tend to skip over flowers that are already occupied by other bees. Unlike native bees, honeybees don’t care if the flower is occupied, so they ‘shoo’ the native bee away as soon as they land on the flower. So, if a native bee saw a honeybee foraging, it’d be polite and go find another flower to feed on, but the rude honeybee doesn’t care.
On watermelon: Kremen et al. (2002) found that interactions between honeybees and native bees were rare, but when they did happen, honeybees did not displace native bees more frequently than native bees displaced honeybees. Abundance was also not negatively affected.
On potted mustard plants and small grassland patches: Steffan-Dewenter and Tscharntke (2000) found that even though there was ~45.5% resource overlap, neither species richness of abundance of wild bees was negatively affected by honeybees.
Basically, there’s a lot of conflicting information. I could keep referencing papers, but I suggest you take a look at this review by Paini and Vivian Huryn, if you’re interested in the topic. Paini reviewed 28 studies investigating the interaction between honeybees and native bees. Huryn looks at interference and exploitative competition.
Based on my observations so far, honeybees are lazy animals. They tend to sit in flowers and can spend over 5 minutes in one. On the other hand, native bees go to a flower, drink and leave in under a minute. So, even if the native bees are displaced by honeybees, I don’t know that the native bees’ fitness would be negatively affected. Also, I’ve seen native bees foraging in flowers with honeybees, so I don’t know if all have the avoidance behavior documented in Gross and Mackay (1998).
In addition to investigating their interactions, a number of studies have determined pollination efficiency of native vs social bees.
I was just reading a paper by A.lexandra-Maria Klein, Steffan-Dewenter, I and Tscharntke, T. (2003) and I had to quote this from their discussion:
The difference in pollination success between these two pollinator guilds could be explained by the following findings: (1) solitary bees switch between plants more often than social bees, thereby offering a higher enhance of cross pollination (Willmer & Stone 1989). (2) Social bees collect less pollen and more nectar than solitary bees and contact the stigma less often (Corbet 1987; Freitas & Paxton 1998). (3) Most solitary bees have longer tongues and therefore make contact with the stigma more often (Corbet 1996). (4) Social, stingless bees often damage flowers, so fruit set may be reduced (Maloof & Inouye 2000; Irwin, Brody & Waser 2001).
I won’t extensively review this topic, but I thought this was interesting. Hope you did too!
Greenleaf, S. S., & Kremen, C. (2006). Wild bees enhance honey bees’ pollination of hybrid sunflower. Proceedings of the National Academy of Sciences of the United States of America, 103(37), 13890–5. doi:10.1073/pnas.0600929103
Gross, C. L., & Mackay, D. (1998). Honeybees reduce fitness in the pioneer shrub Melastoma affine (Melastomataceae). Biological Conservation, 86, 169–178.
Klein, A.-M., Steffan-Dewenter, I. & Tscharntke, T., 2003. Pollination of Coffea canephora in relation to local and regional agroforestry management. Journal of Applied Ecology, 40(5), pp.837–845.
Kremen, C., Williams, N. M., & Thorp, R. W. (2002). Crop pollination from native bees at risk from agricultural intensification. Proceedings of the National Academy of Sciences of the United States of America, 99(26), 16812–6. doi:10.1073/pnas.262413599
Paini, D. R. (2004). Impact of the introduced honey bee (Apis mellifera) (Hymenoptera: Apidae) on native bees: A review. Austral Ecology, 29(4), 399–407. doi:10.1111/j.1442-9993.2004.01376.x
Steffan-Dewenter, I., & Tscharntke, T. (2000). Resource overlap and possible competition between honey bees and wild bees in central Europe. Oecologia, 122(2), 288–296. doi:10.1007/s004420050034
Winfree, R., Williams, N. M., Gaines, H., Ascher, J. S., & Kremen, C. (2007). Wild bee pollinators provide the majority of crop visitation across land-use gradients in New Jersey and Pennsylvania, USA. Journal of Applied Ecology, 45(3), 793–802. doi:10.1111/j.1365-2664.2007.01418.x