The authors are grateful to the European Union grant, programme H2020 entitled: PREHLB:
Preventing HLB epidemics for ensuring citrus survival in Europe. H2020-SFS-2018–2 Topic
SFS-05–2018-2019–2020—new and emerging risks to plant health (Project nº 817526)—as well as to
the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds
FCT/MCTES to CIMO (UIDB/00690/2020) and Associated Laboratory SusTEC (LA/P/0007/2020).
The “citrus greening disease” or huanglongbing (HLB) is caused by the Gram-negative
bacteria Candidatus Liberibacter spp. One vector of HLB, the African citrus psyllid Trioza erytreae
(del Guercio, 1918), was recorded for the first time in 2014, in mainland Spain, and since then, it has
spread throughout the Iberian Peninsula. Spiders could be natural enemies of T. erytreae. In this work,
we assessed the potential of a model spider species, selected according to the most abundant guild
in the field, as a natural enemy of T. erytreae. Theridiidae was the most successful family, capturing
adults of T. erytreae in the field. Kochiura aulica (Theridiidae) was selected as a model for functional
response assays in the laboratory. The effect of web-building plasticity on the functional response of
K. aulica was investigated using two types of arena. The spiders developed tubular-like or branch-like
webs according to the spatial constraints. The web architecture significantly shifted the trapping
efficiency of K. aulica. Functional responses for tubular and branch webs were both Type-II, but
more psyllid prey were captured and killed in the tubular webs than in branch webs. In addition,
significantly more psyllids survived in branch-like webs. Our results suggest that web architecture
is a key factor driving the number of captured adults of the psyllid. Space web builders could be
successful natural enemies of T. erytreae, although further research is needed to clarify the influence
of web-building plasticity on the functional response and trapping efficiency of spiders.
