Digitisation of Pinned Specimens From the Insect Orders Diptera and Hymenoptera Within the New Zealand Arthropod Collection
Biosystematics| Research | Jasmine Gunton
Often not considered by the wider public, museums and other natural history collections play several roles other than to simply entertain or educate. The existence and upkeep of these collections assist research in areas such as biosecurity, natural resource management, and biodiversity research. So just what role can collection research play in solving some of New Zealand’s largest science problems?
Image from Landcare Research Manaaki Whenua - New Zealand Arthropod Collection.
Biological collections can be shared amongst a much larger population through the process of digitisation. Through digitisation, scientists can study specimens from across the world simply by accessing a global database. In a global database, a researcher may be able to find details about an individual specimen’s collection date, location, and morphology [1]. Often, the international non-academic population is also able to reap the benefits of digitisation. For example, London’s Natural History Museum and Boston’s Museum of Science both offer virtual interactive tours of their public collections. Digitisation is therefore an area of focus that collection specialists are beginning to prioritise [2].
However, how does one begin to digitise a collection that has more than 6.5 million specimens? This is the case in the New Zealand Arthropod Collection (NZAC) managed by Manaaki Whenua Landcare Research. Through my research, I aimed to digitise a portion of the NZAC to determine how strategised digitisation could benefit Manaaki Whenua and the wider scientific community.
For some quick context, Manaaki Whenua Landcare Research is a Crown Research Institute that focuses on the environment, biodiversity, and sustainability [3]. Within Manaaki Whenua exists the NZAC, consisting of thousands of pinned specimens and even more specimens held in ethanol. In fact, NZAC has the most complete coverage of terrestrial invertebrates in New Zealand (NZ) [4].
Over the summer, I worked at Manaaki Whenua as a junior lab technician. My research project was to digitise over 2300 Arthropod specimens. These included specimens from the orders Hymenoptera and Diptera. Various details about each specimen’s taxonomic and collection information were recorded on excel spreadsheets. Specimen variables were as follows:
Specimen kind
NZAC accession number
Country
NZ area code
Locality
Altitude
Collection date
Collector name(s)
Collector number
Collection method
Macrohabitat & microhabitat
Collection event notes
Life stage notes
From this mass digitisation project, I was able to collect spatial and temporal data on the NZAC.
For context, the order Hymenoptera includes wasps, bees, and ants. The Diptera order includes various fly families. The specimens digitised in this study were from three families within Hymenoptera and Diptera: Braconidae, Anisopodidae, and Tephritidae. Braconidae is a family of parasitoid wasps within the order Hymenoptera. The species within this family are known to parasitise a large range of crop pests, including the Asian corn borer moth (Ostrinia furnacalis), the tomato hornworm (Manduca quinquemaculata), and the serpentine leafminer (Liriomyza trifolii) [5-7]. Anisopodidae is a family of flies known as wood gnats within the order Diptera. Wood Gnats play an important role in pollinating the Cheesemans spider orchid (Corybas cheesemani), which is endemic to New Zealand [8]. Finally, Tephritidae is a family of fruit flies belonging to the order Diptera. One species of Tephritidae, particularly Bactrocera dorsalis, parasitizes over 250 fruits and vegetables globally [9]. A large proportion of the species within these three families are either beneficial or potentially harmful to the native ecology and/ or agriculture of New Zealand.
The benefits of natural history collections are not solely bound to the population of the locality in which the collection is found.
Figure 1. Total number of digitised Hymenoptera and Diptera specimens by location (Crosby code) in the New Zealand Arthropod Collection (NZAC).
Figure 2. Total number of digitised Hymenoptera and Diptera specimens by year of collection in the New Zealand Arthropod Collection (NZAC). Specimens were collected between 1919 and 2011.
The digitised Diptera and Hymenoptera specimens displayed different spatial and temporal collection trends. Figure 1. shows that most of the Diptera specimens were collected in Auckland (AK) whilst most of the Hymenoptera specimens were collected in Otago Lakes (OL). The spatial Diptera data makes sense considering Auckland is NZ's most densely populated city [10]. However, the spatial collection trends of Hymenoptera specimens do not correlate with the population distribution of NZ. There may be an unusually high sampling effort of Hymenoptera in Otago, or more likely the data was skewed by sampling bias when choosing what species to digitise. Another explanation is that there is a high concentration of Hymenoptera species in the OL region compared to other areas in NZ. We need more information to be sure of either of these theories.
Figure 2. shows that most Hymenoptera specimens were collected around 1980, with another smaller peak around 1996. Most Diptera specimens were collected around 1975, with 4 other significant peaks between 1950 and 1965. Perhaps these statistics show that the Hymenoptera population in NZ grew suddenly in size in the 1980s and that Diptera species showed population growth cycles between the 1950s and 1970s. There is, however, another theory about the cause of the temporal collection trends shown in Diptera and Hymenoptera. Perhaps an increase in collecting effort during certain time periods between the 1950s and 1980s allowed for more insect specimens to be sampled. Although, this does not explain the differences in the Diptera and Hymenoptera temporal trends. Maybe in the 1980s, it was more popular among NZ entomologists to study Hymenoptera than to study Diptera species. As with the cause of the spatial collection trends, we need more information to be sure of the cause of the temporal collection trends of the specimens.
A possible explanation for the difference in temporal collection data between Hymenoptera and Diptera is that it reflects NZ’s changing science policies and goals. As the priorities of NZ entomology shift, this will be reflected in the specimens collected for scientific research. Over the past few decades, NZ science policies have changed to reward innovation over research for the sake of knowledge [11]. Additionally, economic factors and demands have begun to influence scientific research more and more. Therefore, economically important species may be sampled more often during years in which the economic demand is evident.
There are some potential sampling issues within this study. The sample size of ~2300 is far too small compared to the total NZAC size (~1.6 million objects). Additionally, arthropod families were not chosen at random, but rather on the criteria of taxonomic groups that were a priority to finish databasing. Therefore, the sample specimens were likely not representative of all the Hymenoptera and Diptera specimens within the NZAC. Consequently, we cannot extrapolate the results of this study to the entire collection. Additionally, this study alone should not be used for making decisions regarding native arthropod pollination conservation in NZ.
As of May 2022, only 14% of NZAC had been digitised, meaning that any digitisation efforts are beneficial to the greater goal of total digital representation of the collection [12]. Supporting this fact, only 6.2%-12.5% of global natural history specimens were digitised as of 2020 [13]. More funding should be appointed to complete the digitisation of the NZAC and to research methods of mass digitisation via artificial intelligence (AI). Additionally, I would recommend the development of a digitisation precedence framework to determine which taxon should be the priority when choosing which specimens to digitise manually.
I would first like to thank Anna Santure for coordinating the School of Biological Sciences Summer Student Research Programme. Next, I would like to thank my supervisor, Darren Ward, for continually assisting and directing me with my report, presentation, and overall research project. Additionally, I would like to thank my lab partner, Tomas Blokker, for answering any lab questions I had (and for introducing me to the show Twin Peaks). Finally, I would like to thank the other entomologists at Manaaki Whenua who assisted with my internship: Aaron Harmer, Grace Hall, Richard Leschen, and Robert Hoare.
Acknowledgements
[1] J. Lendemer et al., “The Extended Specimen Network: A Strategy to Enhance US Biodiversity Collections, Promote Research and Education,” BioScience, vol. 70, no. 1, pp. 22-30, Jan. 2020. [Online]. Available: https://doi.org/10.1093/biosci/biz140
[2] S. E. Miller et al., “Building Natural History Collections for the TwentyFirst Century and Beyond,” BioScience, vol. 70, no. 8, pp. 674-687, Aug. 2020. [Online]. Available: https://doi.org/10.1093/biosci/biaa069
[3] Manaaki Whenua Landcare Research. “Our Land, Our Future” Manaaki Whenua Landcare Research. https://www.landcareresearch.co.nz/ (accessed 05/03/2023)
[4] Manaaki Whenua Landcare Research. “New Zealand Arthropod Collection [NZAC].” Manaaki Whenua Landcare Research. https://www.landcareresearch. co.nz/ (accessed 05/03/2023)
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[8] M. M. Kelly, R. J. Toft, and A. C. Gaskett, “Pollination and insect visitors to the putatively brood-site deceptive endemic spurred helmet orchid, Corybas cheesemanii,” New Zealand Journal of Botany, vol. 51, no. 3, pp. 155-167, Jul. 2013. [Online]. Available: https://doi.org/10 .1080/0028825X.2013.795905
[9] Y. Qin, C. Wang, Z. Zhao, X. Pan, and Z. Lin, “Climate change impacts on the global potential geographical distribution of the agricultural invasive pest, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae),” Climatic Change, vol. 155, pp. 145-156, Jun. 2019. [Online]. Available: https://doi. org/10.1007/s10584-019-02460-3
[10] Stats NZ, “2018 Census,” Sept. 2019.
[11] S. Leitch, J. Motion, E. Merlot, and S. Davenport, “The fall of research and rise of innovation: Changes in New Zealand science policy discourse,” Science and Public Policy, vol. 41, no. 1, pp. 119-130, Feb. 2014. [Online]. Available: https://doi. org/10.1093/scipol/sct042
[12] D. Ward, A. Harmer, and L. Elder, “Mass Digitisation - Options for Invertebrates,” May 2022.
[13] S. Walton et al., “Landscape Analysis for the Specimen Data Refinery,” Research Ideas and Outcomes, vol. 6, pg. E57602, Aug. 2020, doi: 10.3897/rio.6.e57602
Jasmine is a third-year Bachelor of Advanced Science (Honours) student specialising in Ecology. She is interested in researching areas in insect ecology and ecological restoration. This year she is also a part of the Science Scholars programme.