People have been urged to report sightings of Asian hornets.
The insect, which has been described as "a highly aggressive predator", is likely to be spotted across the county and the UK over the coming months.
Arun District Council said the insect poses a "significant threat to honey bees" and has been spotted in the UK since 2016.
People have been urged to report sightings immediately via the Asian Hornet Watch app, emailing alertnonnative@ceh.ac.uk, or reporting online at nativespecies.org/asianhornet.
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A spokesman for Arun District Council said: "Originally from Asia, in 2004 this invasive non-native species was accidentally introduced to France where it has spread rapidly and into neighbouring countries.
"Since 2016, several sightings have been recorded in the UK.
"It may be seen on flowering plants, around beehives, around rotting / fermenting fruit and protein, and at street markets attracted by sweet fruit and fish stalls and will be active from February to November across England and Wales."
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