Are insect flower visitor assemblages distinguishable between Brassica napus and B. rapa?


  • Brad G. Howlett Plant & Food Research
  • Ruth C. Butler Plant & Food Research
  • Melanie K. Walker Plant & Food Research
  • David A.J. Teulon Plant & Food Research



honey bees, pollination, pollen movement, pollinator movement, New Zealand, non-bee, gene flow, solitary bees, pollinator diversity, bumblebees


Brassica napus and Brassica rapa are grown across six continents for purposes including oilseed, biofuel, vegetables and livestock fodder. Hybridisation between the two can downgrade seed quality reducing grower returns. We assess the similarity of flower visitor assemblages of both species to determine the applicability of pollinator management strategies to both. Insect taxa were collected using window traps placed within ten peak-flowering fields, five each of B. napus and B. rapa (one cultivar/species) located in South Canterbury, New Zealand. Both crops contained similar flower visitor assemblages with 25 of 29 taxa in common. Of the 1549 insects counted, Apis mellifera was most abundant (~40% of individuals in both crops). Bombus terrrestris and the flies Delia platura, and Oxysarcodexia varia were also common. Crop location more likely influenced assemblage composition than crop species. Strategies to boost the role of bee and non-bee pollinators have potential benefits for both crops; however, a broader understanding of pollinator movement between crops is required to optimise seed purity and crop spacing.


AsureQuality Seed Certification Bureau 2009. SCID, New Zealand Seed Crop Isolation Distance Mapping Scheme. 17 p. <a></a> (accessed 7 April 2018).

Chifflet R, Klein EK, Lavigne C, Le Feon V, Ricroch AE, Lecomte J, Vaissiere BE 2011. Spatial scale of insect-mediated pollen dispersal in oilseed rape in an open agricultural landscape. Journal of Applied Ecology 48: 689–696.

Donovan BJ 2007. Apoidea (Insecta: Hymenoptera). Fauna of New Zealand. Christchurch, Zealand Landcare Research Ltd. 295 p.

Evans LJ, Goodwin RM, Walker MK, Howlett BG 2011. Honey bee (<i>Apis mellifera</i>) distribution and behaviour on hybrid radish (<i>Raphanus sativus</i> L.) crops. New Zealand Plant Protection 64: 32–36.

Garibaldi LA, Steffan-Dewenter I, Winfree R, Aizen MA, Bommarco R, Cunningham SA, Kremen C, Carvalheiro LG, Harder LD, Afik O and others 2013. Wild pollinators enhance fruit set of crops regardless of honey-bee abundance. Science 339: 1608–1611.

Garratt MPD, Coston DJ, Truslove CL, Lappage MG, Polce C, Dean R, Biesmeijer JC, Potts SG 2014. The identity of crop pollinators helps target conservation for improved ecosystem services. Biological Conservation 169: 128–135.

Greenacre MJ 2007. Correspondence analysis in practice: Interdisciplinary Statistics. Chapman & Hall/CRC, Boca Raton. 280 p.

Hayter KE, Cresswell JE 2006. The influence of pollinator abundance on the dynamics and efficiency of pollination in agricultural <i>Brassica napus</i>: implications for landscape-scale gene dispersal. Journal of Applied Ecology 43: 1196–1202.

Henning J, Schnitzler FR, Pfeiffer DU, Davies P 2005. Influence of weather conditions on fly abundance and its implications for transmission of rabbit haemorrhagic disease virus in the North Island of New Zealand. Medical and Veterinary Entomology 19(3): 251–262.

Howlett BG, Donovan BJ, McCallum JA, Newstrom LE, Teulon DAJ 2005. Between and within field variability of New Zealand indigenous flower visitors to onions. New Zealand Plant Protection 58: 213–218.

Howlett BG, Walker MK, Newstrom-Lloyd LE, Donovan BJ, Teulon DAJ 2009a. Window traps and direct observations record similar arthropod flower visitor assemblages in two mass flowering crops. Journal of Applied Entomology 133: 553–564.

Howlett BG, Walker MK, McCallum JA, Teulon DAJ 2009b. Small flower-visiting arthropods in New Zealand pak choi fields. New Zealand Plant Protection 62: 86–91.

Howlett BG, Walker MK, Rader R, Butler RC, Newstrom-Lloyd LE, Teulon DAJ 2011. Can insect body pollen counts be used to estimate pollen deposition on pak choi stigmas? New Zealand Plant Protection 64: 25–31.

Howlett BG, Lankin-Vega GO, Pattemore DE 2015. Native and introduced bee abundances on carrot seed crops in New Zealand. New Zealand Plant Protection 68: 373–379.

Howlett BG, Davidson MM, Pattemore DE, Walker MK, Nelson WR 2016. Seasonality of calliphorid and sarcophagid flies across Canterbury arable farms requiring pollinators. New Zealand Plant Protection 69: 290–295.

Howlett BG, Evans LJ, Pattemore DE, Nelson WR 2017a. Stigmatic pollen delivery by flies and bees: Methods comparing multiple species within a pollinator community. Basic and Applied Ecology 19: 19–25.

Howlett BG, Read SFJ, Jesson LK, Benoist A, Evans LE, Pattemore DE 2017b. Diurnal insect visitation patterns to 'Hayward' kiwifruit flowers in New Zealand. New Zealand Plant Protection 70: 52–57.

Magurran AE 2007. Species abundance distributions over time. Ecology Letters 10: 347–354.

McCullagh P, Nelder JA 1989. Generalized Linear Models. Chapman & Hall, London. 511+xix p.

Mesa LA, Howlett BG, Grant JE, Didham RK 2013. Changes in the relative abundance and movement of insect pollinators during the flowering cycle of <i>Brassica rapa</i> crops: implications for gene flow. Journal of Insect Science 13: 13. <a></a>

Payne R, Murray D, Baird D 2017. The Guide to the Genstat Command Language (Release 19). VSN International, Hemel Hempsted, Hertfordshire, UK.

Pordel MR, Hatami B, Mobli M, Ebadi R 2007. Identification of insect pollinators of three different cultivars of winter canola and their effect on seed yield in Isfahan. Journal of Science and Technology of Agriculture and Natural Resources 10: 413–426.

Rader R, Howlett B, Cunningham S, Westcott D, Newstrom-Lloyd L, Walker M, Teulon D, Edwards W 2009. Alternative pollinator taxa are equally efficient, but not as effective as the honeybee in a mass flowering crop. Journal of Applied Ecology 46: 1080–1087.

Rader R, Edwards W, Westcott D, Cunningham S, Howlett B 2011. Pollen transport differs among bees and flies in a human-modified landscape. Diversity and Distributions 17: 519–529.

Rader R, Howlett BG, Cunningham SA, Westcott DA, Edwards W 2012. Spatial and temporal variation in pollinator effectiveness: do unmanaged insects provide consistent pollination services to mass flowering crops? Journal of Applied Ecology 49: 126–134.

Rader R, Bartomeus I, Garibaldi LA, Garratt MPD, Howlett BG, Winfree R, Cunningham SA, Mayfield MM, Arthur AD, Andersson GKS and others 2016. Non-bee insects are important contributors to global crop pollination. Proceedings of the National Academy of Sciences of the United States of America 113(1): 146–151.

Read SFJ, Howlett BG, Jesson LK, Pattemore DE 2017. Insect visitors to avocado flowers in the Bay of Plenty, New Zealand. New Zealand Plant Protection 70: 38–44.

Ronca S, Allainguillaume J, Ford CS, Warren J, Wilkinson MJ 2017. GM risk assessment: Pollen carriage from <i>Brassica napus</i> to <i>B. rapa</i> varies widely between pollinators. Basic and Applied Ecology 19: 36–44.

Stanley DA, Stout JC 2014. Pollinator sharing between mass-flowering oilseed rape and co-flowering wild plants: implications for wild plant pollination. Plant Ecology 215: 315–325.

Stavert JR, Linan-Cembrano G, Beggs JR, Howlett BG, Pattemore DE, Bartomeus I 2016. Hairiness: the missing link between pollinators and pollination. Peerj 4: 18. <a></a>

Stewart AV 2002. A review of <i>Brassica</i> species, cross-pollination and implications for pure seed production in New Zealand. Agronomy New Zealand 32/33: 63–82.

Walker MK, Howlett BG, McCallum JA, Wallace AR, Teulon DAJ 2009. Small arthropods as pollinators in a New Zealand pak choi field trial. New Zealand Plant Protection 62: 92–98.


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How to Cite

Howlett, B.G., Butler, R.C., Walker, M.K. and Teulon, D.A. 2018. Are insect flower visitor assemblages distinguishable between Brassica napus and B. rapa?. New Zealand Plant Protection. 71, (Jul. 2018), 189–197. DOI:




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