The data presented in this blog stem from a project that was part of a summer internship of three undergraduate students conducted in 2015.
A Comparison of Prey Items of Asilidae subfamilies
in the USNM and NMSA Collections
Jonathan Chen | University of Maryland
Karine Camacho | Universidade Federal da Integração Latino-Americana UNILA
Suma Cheru | Wellesley College
Introduction
In this study, we compared the different prey items of Asilidae subfamilies in the USNM (National Museum of Natural History) collection with a data-set based on the NMSA collection (KwaZulu-Natal Museum, Pietermaritzburg, South Africa) as published by Londt (2006, http://hdl.handle.net/10520/EJC32691 ). The five Asilidae subfamilies that were compared in this study include Asilinae, Dasypogoninae, Laphriinae, Stenopogoninae, and Stichopogoninae. While the species were exclusively from the Afrotropical Region in Londt’s publication, the species in the USNM were not sorted based on region, and may have come from any of the zoogeographic regions. The purpose of this study was to observe how the prey orders compared between the exclusive Afrotropical Asilidae species with the Asilidae species in the USNM.
Methods
We first went through the USNM Asilidae collection, which is organized by subfamily, and moved any specimens collected with a prey item and placed them in a cabinet adjacent to main assassin-fly collection. We were then able to assign a unique specimen identifier (USNMENTXXXXXXXX) to each assassin-fly specimen. For each of these specimens, we identified the prey item to order and recorded the data in an Excel spreadsheet. Therefore for each subfamily, we were able to come up with a list of the different prey orders that we found. We were then able to create bar graphs and compare the number and percentages of each prey order for each Asilidae subfamily and compare our results to the data provided by Londt (2006) based on Afrotropical species. In both data-sets, about 2,000 assassin flies with prey items are included.
Results
1. Asilinae
Observations Asilinae
Diptera prey comprises 28.4% of the total prey items of the Asilinae in the USNM and similarly comprises 26.6% of the total prey items of the Afrotropical Asilinae in the NMSA. Londt reports that the Diptera is the dominant prey item for the Asilinae (Londt 2006); however in the USNM, Hymenoptera clearly is the dominant prey item, comprising 36.2% of all prey items found with Asilinae in the collection.
The dominant prey items for Asilinae in the USNM are clearly Hymenoptera and Diptera while the dominant prey items and in the NMSA are Diptera, Hymenoptera, and Orthoptera.
There is a discrepancy between the dominance of Orthoptera as a prey item between the two collections: while it comprises only 8.2% of total prey items for the USNM Asilinae, it comprises 20% of total prey items of Afrotropical Asilinae in the NMSA.
Hemiptera comprises 8.0% of the total prey items of the Asilinae in the USNM and similarly comprises 8.5% of the total prey items of the Afrotropical Asilinae in the NMSA.
Lepidoptera comprises 11.8% of the total prey items of the Asilinae in the USNM and similarly comprises 11.7% of the total prey items of the Afrotropical Asilinae in the NMSA.
Araneae comprises 0.14% of the total prey items of the Asilinae in the USNM and comprises 0.32% of the total prey items of the Afrotropical Asilinae in the NMSA.
Summary data Asilinae
Comparison of the percentages of prey items (sorted to prey order) for the USNM Asilinae* and for the NMSA Afrotropical Asilinae.
|
Prey Order |
USNM Asilidae 3 |
NMSA Afrotropical Asilidae |
|
Blattodea1 |
0.09 % |
0.0 % |
|
Coleoptera |
6.6 % |
14.7 % |
|
Diptera |
28.6 % |
22.0 % |
|
Hemiptera |
7.8 % |
9.6 % |
|
Hymenoptera |
40.2 % |
26.4 % |
|
Lepidoptera |
8.7 % |
8.2 % |
|
Neuroptera |
0.33 % |
1.3 % |
|
Odonata |
1.4 % |
0.2 % |
|
Orthoptera |
5.8 % |
14.0 % |
|
Araneae |
0.47 % |
0.8 % |
|
Archaeognatha2 |
0.0 % |
0.1 % |
|
Ephemeroptera2 |
0.0 % |
0.1 % |
|
Isoptera2 |
0.0 % |
1.2 % |
|
Mantodea2 |
0.0 % |
0.1 % |
|
Mecoptera2 |
0.0 % |
0.2 % |
|
Psocoptera2 |
0.0 % |
0.3 % |
|
Thysanoptera2 |
0.0 % |
0.1 % |
|
Trichoptera2 |
0.0 % |
0.1 % |
|
Undetermined2 |
0.0 % |
0.3 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Asilinae in the NMSA: Blattodea
2 No data for the following prey items of the Asilinae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
3 Specimen USNMENT01115713 (caterpillar) in the USNM Asilinae collection.
* Apocleinae (as used in Londt 2006) combined with Asilinae (see Dikow 2009, http://hdl.handle.net/2246/5949)
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2. Dasypogoninae
Observations Dasypogoninae
Hymenoptera is the most dominant prey item in both the USNM and in the NMSA Afrotropical Dasypogoninae collections, comprising 68.1% and 40.8% of the total prey items, respectively. Diptera is the second-most dominant prey item in both Dasypogoninae collections, comprising 14.4% of total prey items in the USNM and 25.5% in the NMSA Afrotropical Dasypogoninae collection.
Hemiptera comprises 6.9% of the total prey items of the Dasypogoninae in the USNM and similarly comprises 7.1% of the total prey items of the Afrotropical Dasypogoninae in the NMSA.
Lepidoptera comprises 2.5% of the total prey items of the Dasypogoninae in the USNM and similarly comprises 3.1% of the total prey items of the Afrotropical Dasypogoninae in the NMSA.
Summary data Dasypogoninae
Comparison of the percentages of prey items (sorted to prey order) for the USNM Dasypogoninae and for the NMSA Afrotropical Dasypogoninae*.
|
Prey Order |
USNM Dasypogoninae |
Afrotropical Dasypogoninae* |
|
Blattodea1 |
0.0 % |
0.0 % |
|
Coleoptera |
5.6 % |
16.3 % |
|
Diptera |
14.4 % |
25.5 % |
|
Hemiptera |
6.9 % |
7.1 % |
|
Hymenoptera |
68.1 % |
40.8 % |
|
Lepidoptera |
2.5 % |
3.1 % |
|
Neuroptera |
0.28 % |
0.0 % |
|
Odonata |
0.56 % |
0.0 % |
|
Orthoptera |
1.1 % |
0.0 % |
|
Araneae |
0.56 % |
3.1 % |
|
Archaeognatha2 |
0.0 % |
0.0 % |
|
Ephemeroptera2 |
0.0 % |
0.0 % |
|
Isoptera2 |
0.0 % |
3.1 % |
|
Mantodea2 |
0.0 % |
0.0 % |
|
Mecoptera2 |
0.0 % |
1.0 % |
|
Psocoptera2 |
0.0 % |
0.0 % |
|
Thysanoptera2 |
0.0 % |
0.0 % |
|
Trichoptera2 |
0.0 % |
0.0 % |
|
Undetermined2 |
0.0 % |
0.0 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Dasypogoninae in the NMSA: Blattodea
2 No data for the following prey items of the Dasypogoninae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
* Prey counts not precise as the NMSA Afrotropical Dasypogoninae collection includes the Brachyrhopalinae within the Dasypogoninae.
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3. Laphriinae
Observations Laphriinae
Coleoptera comprises 21.9% of the total prey items of the Laphriinae in the USNM and similarly comprises 22.9% of the total prey items of the Afrotropical Laphriinae in the NMSA.
Londt reports that the dominant prey item for Afrotropical Laphriinae is Hymenoptera (Londt 2006). In contrast, the dominant prey item for the Laphriinae in the USNM is Diptera, comprising 32.8% of total prey items. However, in the USNM, Hymenoptera still makes up the second-most dominant prey item, comprising 31.3% of the total prey items.
Londt reports that Coleoptera comprises 81% of prey items for the Laphystiinae (Londt 2006). Combining the Laphystiinae with Laphriinae, it is still evident that Coleoptera is the second-most dominant prey item for Afrotropical Laphriinae, comprising 22.9% of total prey items. Diptera is the third-most dominant prey item for Afrotropical Laphriinae, comprising 19.4% of total prey items.
Summary data Laphriinae
Comparison of the percentages of prey items (sorted to prey order) for the USNM Laphriinae* and for the NMSA Afrotropical Laphriinae.
|
Prey Order |
USNM Laphriinae |
NMSA Afrotropical Laphriinae |
|
Blattodea1 |
1.5 % |
0.0 % |
|
Coleoptera |
21.9 % |
22.9 % |
|
Diptera |
32.8 % |
19.4 % |
|
Hemiptera |
12.4 % |
7.6 % |
|
Hymenoptera |
31.3 % |
42.3 % |
|
Lepidoptera |
0.0 % |
2.8 % |
|
Neuroptera |
0.0 % |
0.0 % |
|
Odonata |
0.0 % |
0.0 % |
|
Orthoptera |
0.0 % |
4.9 % |
|
Araneae |
0.0 % |
0.0 % |
|
Archaeognatha2 |
0.0 % |
0.0 % |
|
Ephemeroptera2 |
0.0 % |
0.0 % |
|
Isoptera2 |
0.0 % |
0.0 % |
|
Mantodea2 |
0.0 % |
0.0 % |
|
Mecoptera2 |
0.0 % |
0.0 % |
|
Psocoptera2 |
0.0 % |
0.0 % |
|
Thysanoptera2 |
0.0 % |
0.0 % |
|
Trichoptera2 |
0.0 % |
0.0 % |
|
Undetermined2 |
0.0 % |
0.0 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Laphriinae in the NMSA: Blattodea
2 No data for the following prey items of the Laphriinae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
* Laphystiinae (as used in Londt 2006) combined with Laphriinae (see Dikow 2009, http://hdl.handle.net/2246/5949)
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4. Stenopogoninae
Observations Stenopogoninae
Neuroptera comprises 0.89% of the total prey items of the Asilinae in the USNM and similarly comprises 0.33% of the total prey items of the Afrotropical Asilinae in the NMSA.
Londt reports that Coleoptera is the most dominant prey item for the Afrotropical Stenopogoninae, comprising 35.1% of total prey items (Londt 2006). However, in the USNM Stenopogoninae collection, Coleoptera is one of the least dominant prey item, comprising only 6.3% of total prey items found with USNM Stenopogoninae.
The most dominant prey item in the USNM Stenopogoninae is Hymenoptera, comprising 41.1% of total prey items, and Diptera is the second-most dominant prey item, comprising 27.7% of total prey items. In the NMSA Afrotropical Stenopogoninae collection, Hymenoptera follows Coleoptera as the second-most dominant prey item, comprising 21.3% of total prey items, and following is Diptera, comprising 14.4% of total prey items.
There is a discrepancy between the dominance of Coleoptera as a prey item between the two collections: while it comprises only 6.3% of total prey items for the USNM Asilinae, it comprises 35.1% of total prey items for NMSA Afrotropical Stenopogoninae. While it is clearly a dominant prey item for the Afrotropical Stenopogoninae, in the USNM, Coleoptera appears to be one of the lesser dominant prey items.
Summary data Stenopogoninae
Comparison of the percentages of prey items (sorted to prey order) for the USNM Stenopogoninae* and for the NMSA Afrotropical Stenopogoninae.
|
Prey Order |
USNM Stenopogoninae |
Afrotropical Stenopogoninae |
|
Blattodea1 |
0.0 % |
0.0 % |
|
Coleoptera |
6.3 % |
35.1 % |
|
Diptera |
27.7 % |
14.4 % |
|
Hemiptera |
5.4 % |
14.1 % |
|
Hymenoptera |
41.1 % |
21.3 % |
|
Lepidoptera |
8.0 % |
2.3 % |
|
Neuroptera |
0.89 % |
0.33 % |
|
Odonata |
10.7 % |
0.66 % |
|
Orthoptera |
0.0 % |
8.9 % |
|
Araneae |
0.0 % |
0.7 % |
|
Archaeognatha2 |
0.0 % |
0.0 % |
|
Ephemeroptera2 |
0.0 % |
0.0 % |
|
Isoptera2 |
0.0 % |
1.6 % |
|
Mantodea2 |
0.0 % |
0.0 % |
|
Mecoptera2 |
0.0 % |
0.0 % |
|
Psocoptera2 |
0.0 % |
0.0 % |
|
Thysanoptera2 |
0.0 % |
0.0 % |
|
Trichoptera2 |
0.0 % |
0.0 % |
|
Undetermined2 |
0.0 % |
0.0 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Stenopogoninae in the NMSA: Blattodea
2 No data for the following prey items of the Stenopogoninae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
* Stenopogoninae (as used in Londt 2006) do not entirely coincide with Stenopogoninae as used at USNM (see Dikow 2009, http://hdl.handle.net/2246/5949)
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5. Stichopogoninae
Observations Stichopogoninae
Diptera is the most dominant prey item in both the USNM Stichopogoninae collection and in the NMSA Afrotropical Stichopogoninae collection.
While the NMSA only had seven prey items corresponding to Afrotropical Stichopogoninae (Londt 2006), the USNM had 72 prey items.
While Coleoptera and Hymenoptera each comprise 14.3% of the total prey items in the NMSA, in the USNM, there are 0% Coleoptera and Hymenoptera.
Summary data Stichopogoninae
Comparison of the percentages of prey items (sorted to prey order) for the USNM Stichopogoninae and for the NMSA Afrotropical Stichopogoninae.
|
Prey Order |
USNM Stichopogoninae |
Afrotropical Stichopogoninae |
|
Blattodea1 |
0.0 % |
0.0 % |
|
Coleoptera |
0.0 % |
14.3 % |
|
Diptera |
86.1 % |
57.1 % |
|
Hemiptera |
5.4 % |
14.3 % |
|
Hymenoptera |
0.0 % |
14.3 % |
|
Lepidoptera |
0.0 % |
0.0 % |
|
Neuroptera |
0.0 % |
0.0 % |
|
Odonata |
0.0 % |
0.0 % |
|
Orthoptera |
1.4 % |
0.0 % |
|
Araneae |
8.3 % |
0.0 % |
|
Archaeognatha2 |
0.0 % |
0.0 % |
|
Ephemeroptera2 |
0.0 % |
0.0 % |
|
Isoptera2 |
0.0 % |
0.0 % |
|
Mantodea2 |
0.0 % |
0.0 % |
|
Mecoptera2 |
0.0 % |
0.0 % |
|
Psocoptera2 |
0.0 % |
0.0 % |
|
Thysanoptera2 |
0.0 % |
0.0 % |
|
Trichoptera2 |
0.0 % |
0.0 % |
|
Undetermined2 |
0.0 % |
0.0 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Stichopogoninae in the NMSA: Blattodea
2 No data for the following prey items of the Stichopogoninae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
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6. All Asilidae
Observations Asilidae
USNM data are in accordance with Londt’s finding that Hymenoptera is the most dominant prey item (Londt 2006). In the USNM, Hymenoptera comprises 40.2% of all prey items and in the NMSA, Hymenoptera comprises 26.4% of all prey items.
There is also no discrepancy between the two collections over which is the second-most dominant prey item. Diptera comprises 28.6% of all prey items in the USNM Asilidae collection and 22% of all prey items in NMSA Afrotropical Asilidae collection. However, when it comes to the third-most dominant prey item, Lepidoptera is the third-most dominant in the USNM, comprising 8.7% of all prey items, while in NMSA Afrotropical Asilidae collection, Coleoptera is the third-most dominant prey item, comprising 14.7% of all prey items.
Summary data Asilidae
Comparison of the percentages of all prey items (sorted to prey order) for the USNM and for the NMSA Afrotropical Asilidae.
|
Prey Order |
USNM Asilidae 3 |
NMSA Afrotropical Asilidae |
|
Blattodea1 |
0.09 % |
0.0 % |
|
Coleoptera |
6.6 % |
14.7 % |
|
Diptera |
28.6 % |
22.0 % |
|
Hemiptera |
7.8 % |
9.6 % |
|
Hymenoptera |
40.2 % |
26.4 % |
|
Lepidoptera |
8.7 % |
8.2 % |
|
Neuroptera |
0.33 % |
1.3 % |
|
Odonata |
1.4 % |
0.2 % |
|
Orthoptera |
5.8 % |
14.0 % |
|
Araneae |
0.47 % |
0.8 % |
|
Archaeognatha2 |
0.0 % |
0.1 % |
|
Ephemeroptera2 |
0.0 % |
0.1 % |
|
Isoptera2 |
0.0 % |
1.2 % |
|
Mantodea2 |
0.0 % |
0.1 % |
|
Mecoptera2 |
0.0 % |
0.2 % |
|
Psocoptera2 |
0.0 % |
0.3 % |
|
Thysanoptera2 |
0.0 % |
0.1 % |
|
Trichoptera2 |
0.0 % |
0.1 % |
|
Undetermined2 |
0.0 % |
0.3 % |
|
TOTAL |
100 % |
100 % |
1 No data for the following prey items of the Afrotropical Dasypogoninae in the NMSA: Blattodea
2 No data for the following prey items of the Dasypogoninae in the USNM: Archaeognatha, Ephemeroptera, Isoptera, Mantodea, Mecoptera, Psocoptera, Thysanoptera, Trichoptera, and Undetermined.
3 The following USNM Asilidae subfamilies had no prey items in the collection: Leptogastrinae, Ommatiinae, and Trigonomiminae.
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Total prey item numbers
Discussion
In the future, the next step in this project would be to sort through the USNM Asilidae prey item collection and sort all the Asilidae based on zoogeographical regions. We would separate subfamilies with prey items based on geography. In this way, we would then be able to compare the predatory habits/prey items between NMSA Afrotropical Asilidae flies with, for example, Nearctic or Oriental assassin flies. Furthermore, we could compare all the USNM Afrotropical Asilidae flies with the Afrotropical Asilidae flies studied by Londt to see if there are any differences.
This would allow us to determine if Asilidae subfamilies have preferential prey items. For example whether one Asilidae subfamily preferentially prey on Coleoptera while another Asilidae subfamily preferentially prey on Hemiptera.