A puzzling lack of honeydew-producing hemipteran insects in the Cape Floristic Region of South Africa

@tonyrebelo @jeremygilmore @ludwig_muller @rjpretor @psyllidhipster @wongun @fabienpiednoir @bnormark @nomolosx @vynbos @peterslingsby @erincpow

Honeydew (https://en.wikipedia.org/wiki/Honeydew_(secretion) and https://www.sciencedirect.com/science/article/abs/pii/B9780123741448001314) is produced by various families of sap-sucking hemipterans in the suborders

• Sternorrhyncha (https://en.wikipedia.org/wiki/Sternorrhyncha), and
• Auchenorrhyncha (https://en.wikipedia.org/wiki/Auchenorrhyncha).

The main sternorrhynchan families involved are

• Aphididae (https://en.wikipedia.org/wiki/Aphididae),
• Aleyrodidae (https://en.wikipedia.org/wiki/Whitefly),
• Psyllidae (https://en.wikipedia.org/wiki/Psyllid),
• Coccidae (https://en.wikipedia.org/wiki/Coccidae),
• Pseudococcidae (https://en.wikipedia.org/wiki/Mealybug),
• Margarodidae (https://en.wikipedia.org/wiki/Margarodidae). and
• Eriococcidae (https://en.wikipedia.org/wiki/Eriococcidae),

(For auchenorrhynchan families see https://www.inaturalist.org/posts/96522-a-puzzling-lack-of-honeydew-producing-hemipteran-insects-in-the-cape-floristic-region-of-south-africa#activity_comment_ad4868eb-6860-4458-b914-3a0659762ec5.)

Honeydew-producing hemipterans are common and diverse in several ecosystems that are

• dominated by evergreen, woody plants,
• nutrient-poor (particularly w.r.t. phosphorus and zinc), and
• prone to wildfire.

The following ecosystems are particularly relevant.

Boreal forest (https://en.wikipedia.org/wiki/Taiga):

The incidence of sap-sucking hemipterans is summarised in https://www.perplexity.ai/search/which-are-the-main-sap-sucking-EM7jj6ifR_y2Oe2cmqAO_Q.

Eucalypt-dominated vegetation in Australia:

https://www.perplexity.ai/search/which-are-the-main-honeydew-pr-QS6kGDpTTjGYw1.ScOdFew

Honeydew is so common in eucalypt-dominated vegetation that honeyeaters (Meliphagidae) often eat this substance in place of nectar (https://www.publish.csiro.au/mu/mu9800213).

Kwongan in Australia:

https://en.wikipedia.org/wiki/Kwongan

https://www.perplexity.ai/search/which-are-the-main-honeydew-pr-Iwn26FAGRvC_JBgVwgLhKQ

At least one family of honeydew-producing hemipterans, viz. Pseudococcidae, is noted for its diversity in the floristically-rich southwestern region of Western Australia (https://www.perplexity.ai/search/which-honeydew-producing-sap-s-4PdFXzbnSziooSPIbxUcYw and https://www.inaturalist.org/posts/96522-a-puzzling-lack-of-honeydew-producing-hemipteran-insects-in-the-cape-floristic-region-of-south-africa#activity_comment_4fdf2d80-eeb1-404c-9aac-4f7225c93fe9).

Cerrado in South America:

https://en.wikipedia.org/wiki/Cerrado

https://www.perplexity.ai/search/which-hemipteran-insects-indig-TiqquV83QTSTUcxhCozDGA

Now, the fynbos biome of South Africa is nutrient-poor and fire-prone (https://en.wikipedia.org/wiki/Fynbos and https://www.sciencedirect.com/science/article/pii/S0254629914002117).

Therefore, we might expect fynbos - and the Cape Floristic Region (https://en.wikipedia.org/wiki/Cape_Floristic_Region) in general - to feature honeydew-producing hemipterans.

However, I have found hardly any information on this in the literature (https://www.perplexity.ai/search/anoplolepis-tends-sap-sucking-tebUgY.xQMuD36uISyJYNg and https://www.perplexity.ai/search/in-southern-africa-which-indig-yHiltTzwTESZjCLocBN0aA and https://www.perplexity.ai/search/in-southern-africa-which-are-t-Yajw5J0hT0GAFWFTNu8Zug and https://www.perplexity.ai/search/is-there-any-literature-on-hon-BNXvvEnVQAS_Gi41Ja.GyA).

Nectariniidae (https://www.perplexity.ai/search/is-any-member-of-nectariniidae-AArpb.xdSre4mi7wy.IwnA) and Promeropidae (https://www.perplexity.ai/search/has-promerops-ever-been-record-WC3kBuvWSGCnV5Nz5jg6hw), common in fynbos, have not been recorded eating honeydew. In this way, they differ from their approximate ecological counterparts, viz. Meliphagidae, in Australia.

It may be relevant that European heathland, superficially similar to ericoid fynbos (https://en.wikipedia.org/wiki/Ericoid), also seems poorly-documented for honeydew-producing hemipterans (https://www.perplexity.ai/search/which-are-the-main-honeydew-pr-N0CYxtJtRMqg9Z9zB2sjRw).

This leaves us with the following question:

Is the dearth of information on honeydew-producing hemipterans in fynbos because of a gap in coverage, or does it reflect a real poverty, indicating some basic and poorly-understood aspect of the functions of the ecosystem?

SUPPLEMENTARY INFORMATION

The following are notes in the biogeography of various clades of honeydew-producing hemipterans.

https://www.perplexity.ai/search/discuss-the-global-biogeograph-J68xinpFToaQOqoSGYJK_g

In the Northern Hemisphere, Aphididae are a major family producing honeydew. In Australia, indigenous Aphididae are ecologically unimportant (https://academic.oup.com/aesa/article/96/2/107/27979). Here,their place is taken by Psyllidae and Pseudococcidae.

In New Zealand, the main indigenous sternorrhynchans that produce honeydew are Margarodidae, Coccidae, and Aphididae.

https://www.perplexity.ai/search/do-psyllid-sternorrhynchans-pr-F84f5VCFQMOSXWN8vNd2Vg

https://www.perplexity.ai/search/pseudococcidae-tend-to-such-sa-Q5pvd3jQQaubsyLEv64Y5Q

https://www.perplexity.ai/search/do-indigenous-psyllids-in-aust-0vrzrZ2mS4SBzhuTNoK2oA

https://www.perplexity.ai/search/which-indigenous-plants-in-new-cRhfuyerSRa6F1RBp9SbKg

https://www.perplexity.ai/search/in-new-zealand-various-indigen-TRnETOxnTbS0xeooSKV8Qg

https://www.perplexity.ai/search/worldwide-which-genera-of-cocc-C7SioRtSQluLN9q0ZM2ISw

https://www.perplexity.ai/search/is-any-member-of-adelgidae-sap-D55Q1W02RoyWA5fzqQjU8Q

https://hal.science/hal-00890589/document

Posted on July 4, 2024 09:54 AM by milewski