Dataset DOI: 10.5061/dryad.j6q573nsc

Description of the data and file structure

Background

Intraguild interference between predators can hamper top-down regulation. For example, aphid-tending ants often defend their mutualistic partners against antagonists. Greater ant aggression against native ladybirds compared to non-native ladybirds might benefit the non-native predator, due to predator-predator naïveté. As a consequence, non-native ladybirds are expected to consume more aphids and might thus outcompete native ladybirds.

Methods

We established microcosms with a bean plant (Vicia faba) infested with black bean aphids (Aphis fabae). The microcosms were divided into the following treatments: no ants, aphids tended by common red ants (Myrmica rubra) and aphids tended by black garden ants (Lasius niger). We added either a native ladybird (Coccinella septempunctata) or an invasive ladybird (Harmonia axyridis) to the microcosms. We compared deterrence of ladybirds from plant-based aphids by ants and the number of aphids remaining at the end of the experiment.

Files and variables

Data_BucherMasson_EcolEntomol_25-0055-EEN.xlsx

The data of this publication is in two sheets presenting the identical data in two different formats: 'data_all' and 'data_per_observ' (and a short version of the information provided below in the sheet named 'meta_data'):

'data_all' shows all data for all observations of [Aphids] and [Plant] with a seperate column for the identity of observation [Observ]

'data_per_observ' shows the same measured variables [Aphids_1], Aphids_2],... and [Plant_1], Plant_2],... per observation time in seperate columns (i.e. repeated measurements of the same microcosm) and the number in the header indicates the identity of the observation (e.g. 1 hour, 2 hours... after the start of the experiment)

In both sheets, variables are defined as:

[No] is the identity of the microcosm (a continuous number)

[Block] indicates the experimental block (i.e. microcosm experiments that were conducted at the same time)

[Observ] is the observation (i.e. repeated measurement) of the respective microcosm measured as number of hours after the start of the experiment; This column occurs only in the sheet 'data_all'

[Treat] is the combination of ant and ladybird treatment, which is the combination of the columns [Ant]_[Beetle], see below

[Ant] is the ant treatment: either MR for Myrmica rubra, LN for Lasius niger, or None for microcosms without ants

[Beetle] is the ladybird treatment: either CS fro Coccinella septempunctata, HA for Harmonia axyridis, or None for microcosms without ladybirds

[Aphids] is the observed number of living aphids in the microcosm (i.e. counts of remaining aphids); This column occurs only in the sheet 'data_all'

[Plant] is the observed position of the ladybird: 1 indicates ladybird is on the plant, 0 indicates ladybird is elsewhere (e.g. on the ground, on the wall/ceiling of the microcosm; This column only occurs in the sheet 'data_all'

[Aphids_1], [Aphids_2],… counts of aphids (see above) at the respective time of observation (1, 2,… hours after the start of the experiment); These columns only occur in the sheet 'data_per_observ'

[Plant_1], [Plant_2],… is the observation of the position of the ladybird (see above) at the respective time of observation (1, 2,… hours after the start of the experiment); These columns only occur in the sheet 'data_per_observ'

[Plant_cum] is the cumulative obervations (sum) of ladybirds observed on the plant (see above) across all observations; This column only occurs in the sheet 'data_per_observ'

Information on NA's:

NA in [Plant] are for treatments without ladybirds ([Beetle] == None) as there is no position of the ladybird if there is no ladybird in the treatment (i.e. not applicable), NA is included here for the use in R*

* Exception: for microcosm 37 we lack the 5th observation of C. septempunctata (i.e. not available; Ladybird might have been hidden in the soil), [Plant_cum] = 0 as the ladybird was never ovserved on the plant in this microcosm

See also information in the sheet 'meta_data' in the file. For more detailed information consult the method section of the article or contact Dr. Bucher via: Roman.Bucher@b-tu.de

Code/software

Excel/R